Fistula treatment devices and related methods

ABSTRACT

Disclosed herein are implantable fistula treatment devices and related methods. The fistula closure device comprises a distal anchor and a proximal anchor attached by a connecting member, such as a suture. Individual porous bodies are threaded directly or indirectly over the connecting member. The distal anchor comprises a plurality of foldable members threaded onto the connecting member. The foldable members are arranged in increasing surface area from distal to proximal, and each is further configured to form a mechanical interfit with adjacent foldable members to reduce sliding between members when they are tensioned together.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. Non-Provisional applicationSer. No. 13/525,161, filed Jun. 15, 2012, which claims priority under 35U.S.C. §119(e) to U.S. Provisional Application No. 61/497,899, filedJun. 16, 2011, and U.S. Provisional Application No. 61/498,495, filedJun. 17, 2011, which are hereby incorporated by reference in theirentireties.

TECHNICAL FIELD

The present invention relates to medical apparatus and methods. Morespecifically, the present invention relates to implantable devices forclosing fistulas and methods of using such devices.

BACKGROUND

Fistulas are a major cause of morbidity and mortality, as there are overone hundred thousand cases of pathologic fistulas a year, which accountfor over ten thousand deaths. They cost the healthcare system billionsof dollars each year to treat.

Fistulas are tissue-lined connections between body cavities and holloworgans or between such cavities or organs and the surface of the body.The fistula tract includes a void or potential void in the soft tissuesextending from a primary fistula opening to a blind ending or leading toone or more secondary fistula openings, sometimes following along tissueplanes of organs or between organs. Fistulas frequently develop as aconsequence of infections or accompany abscess formations. Although somefistulas are purposely created for therapeutic purposes such astracheostomy tracts, gastric feeding tube tracts, or arteriovenousfistulas for dialysis access, pathological fistulas are abnormal tractsthat typically occur either congenitally or form after surgery,surgery-related complications, or trauma. They are most often opentracts that have epithelialized, endothelialized, or mucosalized.

Fistulas can form between almost any two-organ systems, or multipleorgans between different sites of the same organ. For example, they mayoccur between internal organs and skin (enterocutaneous fistulas,gastrocutaneous fistulas, anal fistulas, rectovaginal fistulas,colocutaneous fistulas, vesiclocutaneous fistulas, intestinocutaneousfistulas, tracheocutaneous fistulas, bronchocutaneous fistulas, etc.) orbetween internal organs themselves (tracheal-esophageal fistulas,gastrointestinal fistulas, colovesicular fistulas, palatal fistulas,etc.). Fistulas may also form between blood vessels such asarteriovenous fistulas.

Although fistulas may form in many locations in the body, they arealmost universally highly morbid to patients and difficult forclinicians to treat. For example, enterocutaneous fistulas are one ofthe most feared complications of abdominal surgery. Enterocutaneousfistulas are abnormal connections that form between the bowel and skinand can occur after abdominal surgery, after trauma, or as acomplication of Crohn's disease. Some reports estimate thatenterocutaneous fistulas may form in as many as 1% of patients thatundergo major abdominal surgery. They often require months of supportivecare and/or major abdominal surgery. The overall mortality rate forpatients that develop enterocutaneous fistulas remains high at around20%.

Current options for treatment of enterocutaneous fistulas includelong-term conservative management or major surgery. In a first option,the patients are placed on restricted enteric intake and managed withparenteral nutritional support. The fistula leakage is controlled usinga stoma bag. If the fistula output is high, drains are sometimes placedto try and control the fistula output. Spontaneous closure is relativelylow at around 25%. If fistulas fail to spontaneously close with currentmanagement after 5 weeks of bowel rest, then many surgeons advocatesurgical treatment at this point, though supportive care could continueindefinitely. Patients with open fistula tracts often have ongoingassociated malnutrition and electrolyte imbalance issues as well aschronic non-healing abdominal wounds.

A second option is a major surgery, which has a mortality rate near 30%.The surgery involves resection of the diseased intestinal segment,extirpation of the fistula, and debridement of the fistulous tractthrough the abdominal wall and subcutaneous tissue. This major abdominalsurgery often requires blood transfusion and post-operative ICUadmissions. As a result of chronic inflammation and having abdomens thathave been previously operated on, these patients typically form denseadhesions and have highly friable tissues. In addition, these patientscan be severely malnourished. These conditions make operations onenterocutaneous fistulas extremely difficult and dangerous. After thesurgery the patient is put on total parenteral nutrition (“TPN”) forseveral more days before the patient can be weaned off TPN and slowlyintroduced to normal foods.

Other treatment options may include implantable devices designed to aidin the closure of the fistula. These devices, however, may cause adverseimmunological reactions in patients, may allow leakage of fluid aroundthem, or may migrate or become dislodged when the patient exertshimself, such as during exercise. There is a need in the art for animplantable device for closing a fistula that reduces the chance ofadverse immunological reactions, and the leakage of fluid through thefistula tract, and that has a reduced chance of migration ordislodgement during use.

SUMMARY

Disclosed herein are implantable fistula closure devices and relatedkits and methods. In some embodiments, a distal anchor for animplantable fistula treatment device may comprise a suture, and aplurality of foldable members including at least a distal-most foldablemember and a proximal-most foldable member, wherein the distal-mostfoldable member comprises a suture attachment structure, wherein theproximal-most foldable member is configured to couple to a surface of abody lumen at a distal opening of a fistula, wherein the proximal-mostfoldable member is configured to occlude the fistula at the distalopening, wherein the proximal-most foldable member is configured toslide along the suture attached to the suture attachment structure,wherein the proximal-most foldable member comprises a proximal firstaverage dimension substantially parallel to a longitudinal axis of thesuture, a proximal second average dimension orthogonal to the proximalfirst average dimension, and a proximal third average dimensionorthogonal to the proximal first and second average dimensions, theproximal first average dimension being no greater than 10% of thegreater of the proximal second and third average dimensions, and whereinthe distal-most foldable member comprises a distal first averagedimension substantially parallel to the longitudinal axis of the suture,a distal second average dimension orthogonal to the distal first averagedimension, and a distal third average dimension orthogonal to the distalfirst and second average dimensions, the distal first average dimensionbeing no greater than 30% of the greater of the distal second and thirdaverage dimensions. The distal anchor may comprise at least oneadditional foldable member positioned between the distal-most foldablemember and the proximal-most foldable member. The proximal secondaverage dimension of the proximal-most foldable member of the distalanchor may be larger than the distal second average dimension of thedistal-most foldable member. The distal second average dimension of thedistal-most foldable member of the distal anchor may have less than orequal to 20% of the proximal second average dimension of theproximal-most foldable member.

The proximal-most foldable member of the distal anchor may comprise agenerally circular perimeter. The proximal-most foldable member of thedistal anchor may comprise a generally concave shape. The distal-mostfoldable member of the distal anchor may comprise a generally concaveshape, and a radius of curvature of the distal-most foldable member maybe smaller than a radius of curvature of the proximal-most member.

The distal anchor may comprise coupling members on opposing surfaces ofat least two of the plurality of foldable members. The coupling membersof the distal anchor may comprise complementary protrusions or recesseson the surfaces of the members. The complementary protrusions of thedistal anchor may comprise teeth. The coupling member of at least onefoldable member of the distal anchor may comprise a curing agent. Thecoupling member of the at least one foldable member of the distal anchormay comprise a capsule enclosing the curing agent. The capsules of thedistal anchor may be configured to rupture upon contact with anotherfoldable member. The coupling members of at least two foldable membersof the foldable members may be configured to produce attractingelectromagnetic forces.

Each of the foldable members may decrease in flexibility from theproximal-most to the distal-most foldable member. The proximal firstaverage dimension of the proximal-most foldable member may be less thanthe distal first average dimension of the distal-most foldable member. Adensity of the proximal-most foldable member of the distal anchor may beless than a density of the distal-most foldable member.

A proximal surface of the proximal-most foldable member of the distalanchor may comprise a grapple configured to attach the proximal-mostfoldable member to a surface of the body lumen. A distal surface of theproximal-most foldable member of the distal anchor may comprise agrapple activation structure configured to activate the grapple uponcontact with the proximal surface of another foldable member. Thegrapple activation structure of the distal anchor may comprises aprotrusion.

At least one of the plurality of foldable members of the distal anchormay include a protrusion configured to resist relative movement betweenat least two of the plurality of foldable members. At least one other ofthe plurality of foldable members of the distal anchor may include arecess configured to receive the protrusion. At least one of theplurality of foldable members of the distal anchor may comprise at leasttwo protrusions configured to resist relative movement between the atleast two of the plurality of foldable members.

The distal-most foldable member of the distal anchor may be pre-attachedto the suture at the suture attachment mechanism. The proximal-mostfoldable member may not be pre-attached to the suture.

In some embodiments, a method of sealing a fistula tract may comprisepositioning a first sealing member adjacent a distal opening of afistula tract at a location outside of the fistula tract and positioninga second sealing member against the first sealing member at a locationoutside of the fistula tract, wherein at least one dimension of thesecond sealing member is larger than the first sealing member. Themethod of sealing a fistula tract may also comprise passing the firstsealing member through the fistula tract before positioning the firstsealing member at the location outside of the fistula tract. Positioninga second sealing member in the method of sealing a fistula tract maycomprise positioning an interfit structure of the second sealing memberagainst a complementary interfit structure of the first sealing member.The method of sealing a fistula tract may comprise positioning a thirdsealing member against the second sealing member at a location outsideof the fistula tract, wherein at least one dimension of the thirdsealing member is larger than the second sealing member. The method ofsealing a fistula tract may comprise positioning a porous body withinthe fistula tract after positioning the second sealing member againstthe first sealing member. The method of sealing a fistula tract maycomprise tensioning a tether member attached to the first sealing memberto deform an aggregate distal anchor comprising the first and secondsealing members toward the distal fistula tract. The method of sealing afistula tract may comprise sealing the aggregate distal anchor at anouter edge seal and an inner seal that is spaced apart from the outeredge seal. The method of sealing a fistula tract may comprise securingthe tether to maintain the tensioning of the tether member. Securing thetether in the method of sealing a fistula tract may comprise securingthe tether to a resilient structure.

In some embodiments, a fistula irrigation catheter may comprise atubular member, where the tubular member may comprise a proximal end, adistal end and a wall portion therebetween, the wall portion having aplurality of apertures therethrough, wherein the distalmost aperture ofthe plurality of apertures is located at least about 2 centimeters fromthe distal end of the tubular member, and wherein the plurality ofapertures are oriented to provide non-orthogonal irrigationtherethrough. The plurality of apertures of the fistula irrigationcatheter may be configured to provide bidirectional irrigation. Thefistula irrigation catheter may also comprise a brushing memberconfigured to brush a fistula tract.

In some embodiments, a method of irrigating a fistula tract comprisesinserting an irrigation catheter into the fistula tract, grasping both aproximal end of the irrigation catheter and a distal end of theirrigation catheter, and moving the irrigation catheter proximally anddistally within the fistula tract to irrigate different portions of thefistula tract. The irrigation catheter of the method of irrigating afistula tract may comprise a brushing member, and the method maycomprise brushing the fistula tract.

While multiple embodiments are disclosed, still other embodimentsfistula treatment devices, kits and methods will become apparent tothose skilled in the art from the following Detailed Description. Aswill be realized, the devices, kits and methods are capable ofmodifications in various aspects, all without departing from the spiritand scope of the present invention. Accordingly, the drawings anddetailed description are to be regarded as illustrative in nature andnot restrictive.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is an isometric view of an embodiment of an implantable fistulaclosure device having a segmented body and located in a fistula tract ina compressed or non-expanded state.

FIG. 1B is the same view as FIG. 1A, except the implantable fistulaclosure device is in a non-compressed or expanded state within thefistula tract.

FIG. 1C is an isometric view of the implantable fistula closure devicelocated in a fistula tract in a compressed or non-expanded state, wherethe distal most body of the device body has a conical shape, as opposedto a cylindrical shape.

FIG. 1D is the same view as FIG. 1C, except the implantable fistulaclosure device is in a non-compressed or expanded state within thefistula tract.

FIGS. 2A-2D provide an illustrative depiction of an embodiment of amethod of sealing a fistula tract using a fistula treatment device; FIG.2E depicts an embodiment of a dressing being used with the fistulatreatment device of FIGS. 2A-2D after the fistula tract has been sealed;FIG. 2F depicts an embodiment of a seal or cover being used with thefistula treatment device of FIGS. 2A-2D after the fistula tract has beensealed.

FIGS. 3A and 3B illustrate the sealing of an embodiment of an expandablemember of a fistula treatment device.

FIG. 4 illustrates the actuation of an embodiment of a fistula treatmentdevice to seal the expandable member shown in FIGS. 3A and 3B.

FIGS. 5A-5C depict the sealing of an embodiment of an expandable memberof a fistula treatment device.

FIG. 6A is a perspective view of an embodiment of a proximal anchor of afistula treatment device; FIG. 6B is a side elevational view of theproximal anchor of FIG. 6A; FIG. 6C is a top view of the proximal anchorof FIG. 6A.

FIGS. 7A and 7B provide an illustrative depiction of a method of usingan embodiment of a proximal anchor of a fistula treatment device.

FIG. 8 shows an embodiment of a fistula treatment kit.

FIG. 9A is a side view of an embodiment of a delivery device for animplantable fistula closure device, where a portion of the deliverydevice is inserted into a fistula tract.

FIG. 9B is the same view as FIG. 9A, except the entire delivery deviceis shown inserted into the fistula tract.

FIG. 9C is the same view as FIG. 9A, except the delivery device iswithdrawn from about the device body and the device body is fullyexpanded.

FIGS. 10A-10F are isometric views of a fistula closure deviceillustrating one embodiment of a method of treating a fistula.

FIG. 11 is a perspective illustration of an embodiment of a component ofa fistula treatment device.

FIG. 12 is a perspective illustration of an embodiment of anothercomponent of a fistula treatment device.

FIG. 13A is a superior view of an embodiment of a fistula closure devicecomprising a resilient annular collapsible distal end; FIGS. 13B and 13Care inferior and side elevational views of the device in FIG. 13A.

FIG. 14 is a schematic representation of the device in FIGS. 13A-13Cused with a proximal retaining structure and a plurality of tethered,expandable members attached to the device.

FIG. 15A is a superior view of the proximal retaining structure in FIG.14; FIG. 15B is a schematic side elevational view of an embodiment of adelivery instrument for the device depicted in FIG. 14; FIGS. 15C and15D are examples of an expandable member actuator and delivery catheter,respectively.

FIGS. 16A and 16B depict an exemplary embodiment of a distal anchorcomprising multiple discs in a separated and a collapsed configuration,respectively.

FIGS. 17A and 17B illustrate various embodiments of multi-disc anchorconfigurations.

FIG. 18 is a cross-sectional side elevational view of one example of amulti-disc anchor.

FIG. 19 is a cross-sectional side elevational view of another example ofa multi-disc anchor.

FIGS. 20A-20C depicts various configurations of interdisc interfaces ina multi-disc anchor.

FIG. 21 is a cross-sectional side elevational view of another example ofa multi-disc anchor, without the distalmost portion.

FIG. 22 is a cross-sectional side elevational view of another example ofa multi-disc anchor, without the distalmost portion.

FIGS. 23A-23C depicts various configurations of interdisc interfaces ina multi-disc anchor.

FIG. 24 depicts a tissue-engaging feature of an exemplary anchor.

FIG. 25 is a cross-sectional perspective view of another example of amulti-disc anchor.

FIG. 26 is a cross-sectional perspective view of another example of amulti-disc anchor.

FIG. 27 is a cross-sectional perspective view of another example of amulti-disc anchor.

FIG. 28 is a cross-sectional elevational view of another example of amulti-disc anchor.

FIG. 29 is a cross-sectional perspective view of another example of amulti-disc anchor.

FIG. 30 is a cross-sectional elevational view of another example of amulti-disc anchor.

FIG. 31 is a schematic cross-sectional view of a tissue supportstructure of another example of a multi-disc anchor.

FIG. 32 is a schematic cross-sectional view of a loading device for afistula treatment device.

FIGS. 33A-33B are side elevational and superior perspective views,respectively, of a delivery device for a fistula treatment device.

FIGS. 34A-34B are schematic illustrations of a fistula treatment deviceloaded into the delivery device in FIGS. 33A-33B, in an initial and acollapsed configuration, respectively.

FIGS. 35A-35B are a superior perspective general view and a superiorperspective distal detailed view of an exemplary push device for afistula treatment device.

FIGS. 36A-36B are side elevational and superior perspective distaldetails views of another example of a push device for a fistulatreatment device.

FIG. 37A is an illustrative depiction of an embodiment of a fistulairrigation catheter.

FIG. 37B is a cross-sectional view of a region of the fistula irrigationcatheter of FIG. 37A, where the region includes an aperture.

FIG. 37C is an illustrative depiction of another embodiment of a fistulairrigation catheter.

FIG. 37D is an illustrative depiction of an additional embodiment of afistula irrigation catheter.

FIG. 38A is an illustrative depiction of an embodiment of a fistulairrigation and brushing catheter.

FIG. 38B is an illustrative depiction of a portion of another embodimentof a fistula irrigation and brushing catheter.

FIG. 38C is an illustrative depiction of a portion of an additionalembodiment of a fistula irrigation and brushing catheter.

FIG. 38D is an illustrative depiction of a portion of a furtherembodiment of a fistula irrigation and brushing catheter.

FIG. 39 is an illustrative depiction of an embodiment of a fistulabrushing device.

FIGS. 40A-40C provide an illustrative depiction of an embodiment of amethod of irrigating a fistula tract.

DETAILED DESCRIPTION OF THE INVENTION

Fistula tracts 10 can be nonlinear or curvilinear and contain cavitiesof varying sizes at different intervals within the tract. Fistulas mayalso comprise multiple interconnected passages. An implantable fistulaclosure device 5 disclosed herein employs advantageous design,configuration techniques and attributes to accommodate such constraints.

For example, and referring to FIGS. 1A-1D, in some embodiments, thedevice 5 may have a segmented expandable body 13 formed of a pluralityof individual expandable bodies or members 15 that are coupled together.The members 15 may be coupled together in an immediately adjacentabutting fashion or in a spaced-apart fashion (as shown). Upon insertionof the device 5 into the fistula tract 10 with the expandable members 15in a collapsed or compressed state, the expandable members 15 areallowed to expand to fill the portion of the fistula tract 10 in whicheach expandable member 15 is located. It should be noted that thecollapsed or compressed state allows for convenient insertion of thedevice 5 into the fistula tract 10. Additionally, the segmented natureof the body 13 of the device 5 or, more specifically, the fact that thedevice's body 13 is formed of a plurality of individual members 15,allows the body 13 to be more easily placed in, and to more readilyconform to, the tortuous and diametrically varying configuration of afistula tract 10 when expanded within the fistula tract. Thus, once thebody 13 is allowed to expand within the fistula tract, the devicegenerally completely fills the fistula tract.

In certain embodiments, when the body 13 expands to fill the fistulatract, the device may generally stop, resist or slow fluid flow from thebowel from running out through the fistula tract. The device may do thisby occluding the distal end of the tract via a distal end of the devicebody 13 that is generally non-porous or has an ability to seal thedistal end of the tract. However, generally speaking, a fistula tractwill leak fluid from within the tissue walls surrounding the fistulatract. Some of this fluid will be absorbed by the device. The remainingfluid will drain out of the proximal end of the tract, potentiallythrough the proximal end of the device body 13, which is generallyporous or has the ability to allow the passage of fluids while generallyoccluding or filling the tract.

The time to closure and the necessity for surgery may be reduced (e.g.,significantly) by preventing or reducing bodily fluids that originate atthe distal end of the tract (e.g., bowel fluids) from passing through afistula tract 10 and, in some embodiments, also by reducing the amountor rate of flow through the fistula tract for body fluids originating inthe tract itself. In certain embodiments, the devices 5 disclosed hereinmay reduce or eliminate the passage of fluids through the tract 10 whilealso providing a matrix that promotes tissue growth. The devices 5 maybe utilized to treat a variety of clinically significant fistulas 10, asappropriate, including enterocutaneous fistulas, anal fistulas,bronchopleural fistulas, non-healing g-tube tracts, tracheal-esophagealfistulas, and others.

Referring again to FIGS. 1A and 1B, the device 5 is depicted as locatedin a fistula tract 10 in a compressed or non-expanded state (FIG. 1A)and in a non-compressed or expanded state (FIG. 1B). The device 5includes a proximal end 31, a distal end 32, and the expandable body 13,which is formed of a plurality of individual porous bodies 15 operablyconnected via a connecting member 20. Each porous body 15 includes aproximal end 25 and a distal end 30. Additionally, each porous body 15is adapted to expand from a compressed or non-expanded state (FIG. 1A)to a non-compressed or expanded state (FIG. 1B) after insertion into thetract 10, thereby filling any cavities within the tract 10 andapproximating the fistula tract walls.

As can be understood from FIG. 1A, in some embodiments, when the bodies15 are in a compressed or non-expanded state, the bodies 15 will bespaced apart from each other along the length of the device 5, therebyforming a segmented configuration for the device body 13. In someembodiments, the spaced-apart distances D between adjacent proximal anddistal ends 25, 30 of the bodies 15 in a compressed or non-expandedstate is between approximately zero mm and approximately five mm. In oneembodiment, the spaced-apart distances D between adjacent proximal anddistal ends 25, 30 of the bodies 15 in a compressed or non-expandedstate are between approximately zero mm and approximately 25 mm. Wherethe distance D between immediately adjacent bodies 15 is approximatelyzero mm when the bodies 15 are in a non-expanded state, the bodies 15will be said to be in an abutting or touching configuration, as opposedto a spaced-apart condition. Regardless, the device body 13 will stillbe considered to be segmented on account of the device body 13 beingformed of a plurality of individual porous bodies 15.

In some embodiments, the spaced-apart distances D between adjacentproximal and distal ends 25, 30 of the bodies 15 in a compressed ornon-expanded state are between approximately zero percent andapproximately two and one-half percent of the overall non-expandedlength L of a body 15. Where the distance D between immediately adjacentbodies 15 is approximately zero percent of the length L of a body 15when the bodies 15 are in a non-expanded state, the bodies 15 will besaid to be in an abutting or touching configuration, as opposed to aspaced-apart condition. The device body 13 will still be considered tobe segmented, however, on account of the device body 13 being formed ofa plurality of individual porous bodies 15.

Regardless of whether the bodies are in a spaced-apart configuration oran abutting or touching configuration when the bodies 15 are in thecompressed state, the segmented configuration of the device body 13facilitates the device body 13 being inserted in and conforming to thetortuous diametrically varied route formed by the tract 10.

As can be understood from FIG. 1B, when the bodies 15 are fully expandedwithin the tract 10, the spaced-apart distances D′ between adjacentproximal and distal ends 25, 30 of the bodies 15 in a non-compressed orexpanded state may be between approximately zero mm and approximatelyfive mm. In some embodiments, the spaced-apart distances D′ betweenadjacent proximal and distal ends 25, 30 of the bodies 15 in anon-compressed or expanded state may be between approximately zeropercent and approximately two and one-half percent of the overallexpanded length L′ of a body 15. The expansion of the bodies 15 afterinsertion into the fistula tract 10 allows the device body 13 toapproximate the walls of the fistula tract, as well as fill opencavities. Because the segmented configuration of the device body 13allows the device to closely conform to the tortuous and diametricallyvaried route formed by the tract 10, the bodies 15, when in an expandedstate within the tract 10, generally fill the tract 10 in a manner thatminimizes voids and dead space. Minimizing voids and dead space lowersthe chance of sepsis and other complications.

While a segmented body 13 has been described, some embodiments of tissuetreatment devices may comprise a non-segmented body (i.e., a body 13that is a continuous, single-piece body 13 as opposed to being formedfrom multiple bodies 15).

Any suitable methods may be used to deliver or deploy the fistulatreatment devices described herein.

In one embodiment, and as illustrated in FIGS. 10A-10F, the device 5 maybe loaded in a lumen of a catheter, sheath or guidewire. As can beunderstood from FIGS. 10A and 10B, the loaded catheter or sheath 900 orguidewire (not shown) is then inserted into the tract 10. Next, and asshown in FIG. 10C, the loaded catheter or sheath 900 or guidewire iswithdrawn from about the device body 13 to leave the device body 13within the tract 10. As indicated in FIGS. 10C-10F, the device body 13then softens and/or expands to fill and occlude the tract 10. Asillustrated in FIG. 10F, a proximal clip 1000 may be used at theproximal end of the device 5 to further secure the device 5 in the tract10. Other proximal members may alternatively or additionally be used, asappropriate, and as discussed in more detail below.

In another embodiment, and as shown in FIGS. 9A-9C, the catheter orsheath may be a dual lumen catheter 900, where one lumen contains thedevice 5 and the other lumen contains a guidewire 901. In certainembodiments, the catheter may be a multi-lumen catheter where at leastone lumen is shaped like a “D”. In some embodiments, a delivery devicemay include a central or main lumen through which the fistula closuredevice 5 may pass and a secondary lumen through which the guidewire 901may pass. As can be understood from FIGS. 9A and 9B, the guidewire 901is inserted into the fistula tract 10 and the catheter 900 is trackedover the guidewire 901. As shown in FIG. 9C, the device 5 is deployedand the catheter 900 is withdrawn from about the device body 13 to leavethe device body within the tract 10. The device body 13 then expands tofill and occlude the tract 10.

In some embodiments, a catheter comprising a peel-away sheath may beused. For example, a skive, score, partial cut, mechanical joint orformed groove may create a longitudinally extending stress concentrationfor causing the catheter to peel along the stress concentration.

In certain embodiments, the delivery device 900 may be tracked over aguidewire 901 with the fistula occlusion device 5 residing in the mainlumen. Once properly positioned in the fistula tract, the deliverydevice 900 can be removed from about the closure device 5. The removalof the delivery device 900 from about the closure device 5 may beaccomplished by grasping an exposed portion of the delivery device 5 ora grasping member, for example, and then pulling or pushing the deliverydevice relative to the closure device 5. Alternatively, a hooked memberhaving a hook or other engagement feature that engages an end of thedelivery device 900 may be employed where the hooked member can be usedto pull the delivery device 900 from about the closure device 5.

In other embodiments, the device 5 may be deployed via a guidewire witha hook-like feature at one end. Such a delivery device can be used foran anal fistula 10, where there is access at both a proximal and adistal end of the fistula tract 10 (in contrast to an enterocutaneousfistula, which has one external access point). The guidewire with thehook-like feature may be inserted into the fistula tract at a first endand passed through the tract 10 such that it can be used to pull thedevice 5 through the tract 10 by the hook to a second end. The distalend of the device 5, which may already be in an expanded state, mayanchor the device 5 into the fistula tract. This embodiment of thedelivery device may reduce the amount of work required of the surgeon asthe hook may be used to pull the delivery device into place. In anadditional embodiment, a guidewire or stylet may be extended through thedevice body 13 generally parallel to the connecting member 20. In otherwords the device body 13 may be threaded onto the guidewire or stylet.The guidewire or stylet may then be used to negotiate the device body 13into the tract 10. Once positioned in the tract 10, the stylet orguidewire may be withdrawn from the device body 13. Where the devicebody 13 is threaded onto the stylet or guidewire, the bodies 15 may haveholes therein for receiving the stylet or guidewire. Also, the bodies 15may have slots through their sides that lead to the holes so the styletor guidewire can be inserted into the holes without having to be placedtherein via a threading motion. In versions of such embodiments, theslots and/or holes in the bodies 15 for receiving the stylet orguidewire in a threaded arrangement are configured to close after thestylet or guidewire is withdrawn from the bodies 15. The closure of theslots and/or holes may result from the expansion of the bodies 15.

Regardless of whether a catheter, sheath, guidewire or stylet orcombination thereof is used to deploy the device 5 in the tract 10, oncelocated within the tract 10, the device body 13 will begin to expand andfill the voids of the tract 10. Expansion of the bodies 15 may be aresult of being free of the constraints of the lumen of the sheath,catheter or guidewire used to deliver the device 5. Expansion of thebodies 15 may be a result of being free of the constraints of arestraining mechanism such as a biodegradable ring, sheath, member, etc.extending about the bodies 15 when first deployed in the tract 10.Expansion may be a result of being exposed to body fluids or temperaturewithin the tract 10. Expansion may be a result of any one or more ofthese aforementioned expansion methods.

As can be understood from FIG. 1B, the porous bodies 15 at the proximaland/or distal ends 31, 32 of the device 5 may be configured to protrudefrom the distal and/or proximal fistula openings when implanted in thefistula tract 10. As depicted in FIG. 1B, the protruding end 115 of themost distal body 110, or the entirety of the most distal body 110, maybe configured to expand more than the rest of the porous bodies 15. Suchan over-expanding capability at the distal ends 32 of the device 5 whenwithin the fistula tract may produce an occluding and anchoring effect.Additionally or alternatively, the same concept may be applied to themost proximal body 15 at the device proximal end 31. Such embodimentscan be considered to have at least one body 15 with a magnitude ofexpansion that is different from (i.e., exceeds) the magnitude ofexpansion of the other bodies 15. In one embodiment, a device 5 with adistal most body 110 that is configured to have increased expansion ascompared to its fellow bodies 15 will be positioned in the tract 10 suchthat the most distal body 110 is partially within the tract 10 andpartially extending from the distal opening 12 into, for example, thebowel lumen. Thus, as illustrated in FIG. 1B, once the distal portion ofthe device 5 is in place, the distal most body 110 of the device 5expands to contact the edges of distal opening 12 of the fistula tract10, thereby occluding the distal opening 12 of the fistula tract 10. Thedevice 5 also expands to fill the rest of the fistula tract 10. Tofacilitate a generally complete sealing of the distal opening 12, thedistal most body 110 of the device 5 may include an impermeable coating.

In a manner similar to that discussed above with respect to the distalmost body 110, the proximal most body at the proximal end 31 of thedevice 5 may be adapted and configured to anchor or otherwise hold thedevice 5 in place within the fistula tract. Where both the distal andproximal most bodies are so configured, the distal and proximal mostbodies will provide a counter force or counter balance to each otherthrough the connecting member 20. In some embodiments, the proximal mostand/or distal most bodies may be or include an adhesive layer to furtherstrengthen the seal around the respective fistula tract openings.

For a discussion of distal most or proximal most bodies 15 having shapesother than generally cylindrical, reference is made to FIGS. 1C and 1D,which are respectively the same as FIGS. 1A and 1B, except illustratingthe differently shaped bodies 15. As shown in FIGS. 1C and 1D, thedistal most body 120 may have a shape that is non-cylindrical and, morespecifically, conical. While not shown here, in some embodiments, theproximal most body 15 at the proximal end 31 of the device 5 may alsohave a conical shape as opposed to a cylindrical shape.

In some embodiments, the conically shaped most distal body 120 isgenerally shaped such that its distal end 125 is generally greater indiameter than its proximal end. The distal end 32 of the device 5 may beadvanced into the distal opening 12 of the fistula tract 10 such that adistal portion 125 of the body 120 extends from the tract opening 12into, for example, the bowel lumen. As illustrated in FIG. 1B, once thedistal end of the device 5 is in place, the distal end 125 of the body120 expands to contact the edges of the distal opening 12 of the fistulatract 10, thereby occluding the distal opening 12 of the fistula tract10. The rest of the device body 13 also expands to generally fill therest of the fistula tract 10 as described above. In some embodiments,the proximal end 31 of the device 5 does not extend beyond the edge ofthe fistula tract, while in other embodiments it does.

In some embodiments, the difference in diameter of the distal end 125could be a result of a difference in the distance by which the differentparts of the distal body 120 can expand. For example, the diameter ofthe cylinder in the compressed or non-expanded state is uniform;however, when the cylinder expands, the proximal end of the cylinder mayreach the wall of the fistula tract 10, while the distal end may have agreater distance to expand before reaching the wall of the fistula tract10 which corresponds to its target area of expansion. In this case, thediameter of the cylinder in a non-expanded state is uniform, but thediameter of the cylinder in the expanded state forms a conical shape.

In FIGS. 2A and 2B, the device body 13 is similar to that discussedabove with respect to FIGS. 1A and 1B, in that the device body 13includes individual porous bodies 15 (delivered here by a deliverycatheter 280) coupled together via a connecting member 20. However,here, and as indicated in FIGS. 2A and 2B, the distal end 32 of thedevice 5 terminates in an expandable member 200, which is coupled to thedistal end of the connecting member 20. The expandable member 200 servesto anchor the device distal end in place at the fistula distal opening12 and/or to seal the fistula distal opening 12.

The expandable member 200 may have any appropriate configuration, and insome cases may include a gel-filled or otherwise readily deformablemember sandwiched between a pair of generally rigid discs. In someembodiments, the expandable member 200 may be shaped like a wagon wheel,with the outer rim being the sealing part and the spokes helping todistribute air and/or any other suitable inflation fluids. Theexpandable member 200 may, for example, comprise a generally flat andcircular configuration, or may be thicker and non-circular, includingoval or rectangular shaped devices. Although the expandable member 200is depicted as comprising a generally planar configuration, in othervariations, the expandable member may comprise a concave proximalsurface and a convex distal surface, which can resiliently deform towarda flattened or everting configuration

The expandable member 200 may be configured to be collapsed for deliveryto the target location and to re-expand when deployed. In some examples,the expandable member 200 may comprise a resilient material thatre-expands upon removal of any restraint acting on the collapsed body,such as the removal or withdrawal of a delivery catheter, or thecessation of suction or vacuum acting on the collapsed body. Forexample, the body may be molded (e.g., injection or blow molded) usingpolyurethane, polyvinyl chloride or any other suitable resilientpolymeric material into its base configuration that may then becollapsed using suction or vacuum. In some examples, the expandablemember 200 may comprise a shape-memory or superelastic material,including but not limited to nickel-titanium alloys or shape-memorypolymers. In other examples, re-expansion may be facilitated by theinfusion or inflation of a liquid or gas into the expandable member 200.The expandable member 200 may generally comprise any suitable materialor materials. For example, in some cases the expandable member 200 maycomprise one or more biocompatible polymers and/or one or morebiodegradable or bioabsorbable materials. Expandable members aredescribed, for example, in U.S. Patent Application Publication No. US2010/0228184 A1, which is incorporated herein by reference in itsentirety.

As shown in FIG. 2A, the delivery catheter 280 may be advanced (e.g.,over a suture) to the target site. In some cases, the delivery catheter280 may be advanced to the target site through a sheath (not shown).Once the distal end of the delivery catheter 280 is positioned at thetarget site, an actuator (not shown) may be inserted into the deliverycatheter 280 until it is positioned against the proximal most expandablemember 15. The position of the actuator may then be maintained while thedelivery catheter 280 is proximally withdrawn to deploy the expandablemembers 15 into the fistula tract 10. The actuator and the deliverycatheter 280 may then be proximally withdrawn from the sheath. It shouldbe understood that this is only one example of a delivery method, andother suitable delivery methods may also be used, as appropriate.

In some embodiments, the expandable member 200 may comprises at leastone inflatable balloon, chamber or cavity. The inflatable balloon may,for example, be advanced in a non-inflated state through the distalopening 12 of the fistula tract 10. Once in position, the balloon may beinflated (e.g., via a lumen in the connecting member 20) with a materialsuch as air or saline, or another biocompatible fluid or solidifyinggel. The balloon may be a fluid-inflatable or expandable disc-shapedballoon adapted to occlude the distal tract opening. Alternatively, theballoon may be a fluid-inflatable or expandable flat cone-shaped balloonadapted to occlude the distal tract opening. Other suitable shapes orconfigurations may also be used, e.g. a curved configuration with adistal convex surface and a proximal concave surface, as mentionedearlier. Tension may then be applied to the device 5 via the connectingmember 20, to thereby cause the balloon to occlude the distal opening 12of the fistula tract 10. In some variations, the expandable member 200may be sufficiently resilient to achieve its expanded configuration whenany collapsing force or structure is removed, but wherein the inflationchambers may be used to alter the resiliency, rigidity or othermechanical characteristics of the expandable member.

In some embodiments, one or more actuation mechanisms may be used toexpand the expandable member 200, while in other embodiments, theexpandable member 200 may be expanded without any actuation mechanisms.For example, the expandable member 200 may expand upon exposure to bodyfluids or a temperature differential within the tract 10, or via its ownbiased nature. In addition to the expandable member 200 expanding toanchor the device 5, the device body 13 expands to generally fill therest of the fistula tract 10 as described above, and as depicted in theprogression from FIG. 2A to FIG. 2C.

In some embodiments of a fistula closure device 5 equipped with anexpandable member 200, the device 5 and its expandable member 200 in anon-expanded state are configured to pass through a lumen of cathetersize of nine French or smaller, and in some embodiments, twenty Frenchor smaller.

In certain embodiments, the expandable member 200 may comprise anadhesive coating adapted to adhere to the tissue surface of the regionadjacent the distal opening 12 of the fistula tract 10, while in otherexamples, the adhesive may be light curable, where the light is providedvia a fiberscope inserted into the fistula tract (with or without thedelivery tool or a cannula in place), or in some variations, via thelumen of the gastrointestinal tract. The adhesive may activate afterexposure to a fluid (e.g., body fluid) or body temperature. The adhesivemay initially strengthen the bond of the member 200 to the tissue andthen gradually degrade in strength as fistula tract healing occurs orafter fistula tract healing. Depending on the embodiment, the adhesivemay create a fluid impermeable seal for at least 7, 14, 21, 28, 35, 60or any other number of days.

In certain embodiments, an expandable member 200 may include attachmentmembers, such as micro hooks or tines. Such attachment members may belocated on a surface of the expandable member 200 intended to contactthe tissue surface area forming the opening 12, thereby facilitating theadherence of the expandable member to the tissue surface bordering thedistal tract opening and the occlusion thereof.

In some embodiments, an expandable member 200 or various componentsthereof may be resorbable and adapted to occlude the fistula tract andthen resorb after the tract 10 has closed at least about 45%, 55%, 65%,75%, 85%, 95%, 100% or any other percentage. The expandable member 200or various components thereof may be biodegradable and/or adapted tofall away from the distal fistula opening 12 and be extruded through thegastrointestinal tract. For example, the expandable member 200 orvarious components thereof may be secreted from the body after the tract10 has progressed towards closure (e.g., after at least 7, 14, 21, 28,35 or any other number of days adequate to achieve sufficient closure).

In some embodiments, the connecting member 20 may be a biocompatiblepolymer string extending through the tract from the expandable member200. The connecting member 20 may be formed of one or more resorbablematerials and may resorb after the tract 10 has closed at least about45%, 55%, 65%, 75%, 85%, 95%, 100%, or a percentage range between anytwo of the above percentages. The connecting member 20 may providetensile force substantially perpendicularly to the expandable member200, thereby pulling the expandable member 200 against the tract'sdistal opening 12 and anchoring the expandable member 200 in place toocclude the distal tract opening.

Expandable members or components 200 may have any suitable shape orconfiguration, and may be actuated using any appropriate mechanism. Insome cases, a plugging mechanism may be used to seal an expandablemember 200 (e.g., after the expandable member has been positioned at atarget site and expanded). For example, FIGS. 3A and 3B show anexpandable member 200 coupled to a connecting member 20 (e.g., that maybe used for loading one or more porous bodies 15), where a plug member300 is used to seal the expandable member when it is expanded. As shown,the plug member 300 comprises a plug portion 302 and an elongated member304 (e.g., a suture) coupled to or integral with the plug portion. Theexpandable member 200 in this embodiment comprises a disc-shaped portion306 and a tip portion 308, although other configurations may also beused. In FIG. 3A, the expandable member 200 has not yet been sealed.However, in FIG. 3B, the plug member 300 has been actuated to move theplug portion 302 into the tip portion 308 of the expandable member, andto thereby seal an aperture 310 in the tip portion. The plug member 300may be actuated, for example, by proximally withdrawing the elongatedmember 304 (i.e., in the direction of arrow 312). While not depictedhere, in certain embodiments, it may also be possible to undo the seal(e.g., by pushing on the elongated member 304 and thereby disengagingthe plug portion 302 from the tip portion 308).

FIGS. 5A-5C similarly depict the sealing of an embodiment of anexpandable member 200. First, as shown in FIG. 5A, the expandable member200 has been delivered to the target site, but is not yet sealed. Thedelivery catheter 500 engages ribs 502 of the tip portion 308 of theexpandable member 200 and thereby stabilizes the position of theexpandable member 200. In some embodiments, the expandable member 200may be expanded by injecting inflation fluid in the proximal end of thedelivery catheter 500, such that the inflation fluid travels through thedelivery catheter 500 into the expandable member 200 and therebyinflates the expandable member 200.

In FIG. 5B, the elongated member 304 has been proximally withdrawn tomove the plug portion 302 into the aperture 310 in the tip portion 308of the expandable member 200. This positions the plug portion 302 in thesealing position, where it seals the expandable member 200. As shown,the plug portion 302 now engages ribs 506 of the tip portion 308 of theexpandable member 200. Finally, FIG. 5C shows the sealed expandablemember 200, when the delivery catheter 500 has been disengaged therefrom(e.g., by being proximally withdrawn).

While plug members comprising elongated members and plug portions havebeen described, other embodiments of plug members having differentcomponents and/or configurations may also be used, as appropriate. Forexample, a plug member may comprise multiple plug portions and/or a plugportion having a different configuration.

Once the expandable member 20 has been expanded, it may be used to sealthe distal opening of a fistula tract. FIG. 4 depicts the actuation of adelivery instrument 1550 (shown in its entirety in FIG. 15B), by pullingon the tether 1424 in the direction of arrow 402, to tension the tetherand thereby seal the distal opening of the fistula tract 10 withexpandable member 20. While one actuation mechanism is shown, otherappropriate actuation mechanisms may alternatively or additionally beused.

As discussed above, in some embodiments of the device 5, the proximalend of the device may be adapted and configured to receive a proximalclip that secures the device in place. The clip may, for example, bedisc-shaped, or may have a different (e.g., polygonal) shape. The clipmay be made of any biocompatible material, such as PGLA, PVA or PVC, orany other suitable biocompatible polymer or plastic. The material mayalso be resorbable. In use, the clip may extend across the proximal endof the fistula tract 10 and may be generally flush or slightly raisedrelative to the proximal end of the fistula tract 10. The clip may helpto maintain tension on the connecting member 20 that couples theexpanding member 50 with the clip, thereby helping to maintain or anchorthe device 5 in the tract 10. The clip may be coupled to the connectingmember 20 in any appropriate fashion, such as via friction, pinching,suturing or any other suitable method.

Features of the clip and/or proximal end 31 of the device 5 may betransparent to allow visual inspection of the tract. In someembodiments, the clip and/or proximal end of the device may be adaptedto cover the proximal end of the fistula tract without completelysealing the proximal end of the tract, thereby allowing accumulatingfluids to drain or escape from the proximal end of the tract. In somecases, the clip may comprise a mesh-like membrane that permits drainageof accumulating fluids from the proximal end of the tract. After thetract 10 heals, the proximal clip may resorb or otherwise be removed.

Referring back to FIGS. 2C-2F, in addition to effectively anchoring thedistal end of a device 5 (as shown, using an expandable member 200), theproximal end of a device may also be stabilized or positioned with aproximal anchor 250.

In FIGS. 2C-2F, tethers 254 and 256 that are attached to the expandablemember 200 may be used to apply tension to the expandable member 200 tothereby seal the fistula tract 10. In some examples, at least one of thetethers (e.g., tether 256) may be provided to as a guide element fordelivery of the expandable members 15 of the body 13 along the fistulatract 10. At least one or both of the tethers 254 and 256 may be securedusing the proximal anchor 250. This securing of the tethers 254 and 256makes distal sliding or displacement of one or both of the tethers lesslikely, as the proximal anchor 250 provides an increased surface area ortransverse dimension that resists collapse or entry of the proximalanchor 250 into the fistula tract. The proximal anchor 250 may help tomaintain the tension in one or both of the tethers 254 and 256.

In use, the proximal anchor 250 may be slid onto one or both of thetethers and positioned adjacent the skin surface (e.g., after theexpandable members 15 have been expanded in the fistula tract 10 by, forexample, infusing saline into the fistula tract). While maintainingtension on the tension tether 254 through the proximal anchor 250, thedelivery tether 256 may be sutured or otherwise attached to thesurrounding tissue using a free needle passed through the proximalanchor 250 and tied to the tissue with the desired tension. At alocation opposing the delivery tether 256 on the proximal anchor 250, afree needle may be used to pass through the proximal anchor 250 and tosuture the tension tether 254 to the surrounding tissue. Additionalsutures (e.g., 3-0 or 4-0 nylon) may be used to further secure theproximal anchor 250 to the surrounding superficial tissue as needed.

The size and shape of the proximal anchor 250 may depend, for example,upon the particular fistula being treated. In some embodiments, theproximal anchor 250 may have a diameter or maximum transverse dimensionthat is at least the same as that of the expandable member 200. Infurther examples, the diameter or maximum transverse dimension may be atleast two times, three times, or four times or greater than thecorresponding dimension of the expandable member 200. The expandablemember 200 and the proximal anchor 250 may both have the same shape(e.g., circular) or may have different shapes.

The proximal anchor 250 may also comprise one or more securing apertures258 that may permit the attachment of the proximal anchor 250 to theskin or a bandage surrounding the dermal fistula opening. These securingapertures 258 may be spaced around the periphery of the proximal anchor250, closer to the outer edge rather than the center of the proximalanchor 250. Any suitable number of apertures having any appropriate sizemay be used. In other examples, the proximal anchor 250 may comprise anadhesive surface that contacts the skin surrounding the fistula andresists movement. The tethers 254 and 256 of the device may be securedto the proximal anchor 250 by any of a variety of mechanisms, includinga clamping structure, adhesive, or by a deformable slit that provides areleasable friction fit interface for the tethers 254 and 256. Theattachment site of the tethers 254 and 256 on the proximal anchor 250may further comprise access openings that may be used to infusetherapeutic agents into the fistula, and/or to permit passive or activefistula drainage, or the application of negative pressure therapy to thefistula.

FIG. 2C depicts a proximal anchor 250 comprising just a single body 259.However, in FIGS. 2D and 2E, the proximal anchor 250 is depicted ascomprising a first portion 260 and a second portion 262 that is movablycoupled to the first portion by a plurality of resilient members 264.The first portion 260 is the more distal portion of the proximal anchor250, and may have a tissue contact surface 266 that is configured toresist passage into a fistula of the type being treated (e.g., anenterocutaneous fistula). The first portion 260 also comprises anaperture 267 that permits slidable coupling to at least one tether(e.g., tethers 254 and 256). The second portion 262 is the more proximalportion of the proximal anchor 250, and comprises a tether-fixingstructure 268 configured for affixation of at least one tether (e.g.,tethers 254 and 256) thereto. For example, at least one tether may betied to the tether-fixing structure 268.

During use, when the first and second portions 260, 262 are coupled to atether, the first and second portions can move relative to each other toaccommodate changes in the length of tether between them. For example,movement by the patient may necessitate having a lesser or greaterlength of tether between the first and second portions. The ability ofthe first and second portions to move relative to each other may allowfor such a change to take place without, for example, resulting intether breakage or excessive tether slackness. While the first andsecond portions 260, 262 of the proximal anchor 250 of FIGS. 2D and 2Eare allowed to move relative to each other as a result of the resilientmembers 264, in other embodiments, different portions of a proximalanchor 250 may be movably coupled to each other in other ways, asdiscussed in additional detail below.

It should be noted that any of the proximal anchors described herein maybe configured to allow for negative pressure transmission (e.g.,negative pressure wound therapy), as appropriate. For example, theproximal anchors may include one or more apertures configured fornegative pressure wound therapy. A vacuum pump may be applied to suctionout fluid and/or collapse dead space to facilitate healing.

FIGS. 6A-6C provide enlarged views of the proximal anchor 250 comprisingfirst and second portions 260, 262. As shown in FIG. 6B, proximal anchor250 has an overall height 292, first portion 260 has dimensions 290 and294, and second portion 262 has dimensions 296 and 298. In someembodiments, overall height 292 may be from about 0.25 inch to about0.75 inch, dimension 290 may be from about 0.5 inch to about 1.5 inches,dimension 294 may be from about 0.1 inch to about 0.5 inch, dimension296 may be from about 0.15 inch to about 0.5 inch, and/or dimension 298may be from about 0.05 inch to about 0.25 inch. Proximal anchor 250 maybe made of any suitable material or materials, including but not limitedto polymers, metals (e.g., titanium) and/or metal alloys (e.g.,stainless steel). First and second portions 260, 262 may comprise thesame material or materials, or may comprise different materials. Incertain embodiments, resilient members 264 may comprise one or moremetal alloys, such as Nitinol.

Referring to FIG. 2E, in some cases, an absorbent dressing 270 may bepositioned securely on top of the proximal anchor 250 to absorb anyexcess drainage that may occur. Alternatively, active drainage of thefistula/wound may be performed using wound drainage products or negativepressure wound therapy products. In certain cases, a proximal anchor maybe configured both to accommodate negative pressure wound therapy and toaccommodate an absorbent dressing. Also, prophylactic antibiotics may beoptionally provided post-procedure. In some cases, and referring now toFIG. 2F, a protective cap 272 (e.g., that may be relatively rigid) maybe provided over the proximal anchor 250. The protective cap 272 may,for example, be formed of one or more polymers, metals and/or metalalloys. As shown, the protective cap may comprise at least one vacuumport 274 (e.g., to allow for negative pressure wound therapy).

FIGS. 7A and 7B show an alternative embodiment of a proximal anchor 250,in which the direction of force is parallel with the skin surface. Inother words, here the tether is tensioned with a force that generally isnot directed outward from the body. Drag on the tether may be reduced byusing a large radius for the transition in which the tether changesdirection during use. The embodiment shown in FIGS. 7A and 7B has aninterlocking design that advantageously would minimize the spacerequired to accommodate a relatively long tether length, while stillallowing for tether movement. More specifically, in FIGS. 7A and 7B, theproximal anchor 250 comprises a frame member 700 and first and secondportions 702, 704 that are slidably coupled to the frame member and thatare configured to interlock with each other. While one interlockingconfiguration is shown, other configurations (e.g., using differentinterlocking shapes) may also be used, as appropriate.

The first and second portions 702, 704 of the proximal anchor 250comprise protruding members or pegs 706 through which at least onetether (here, the tension tether 254) may be routed. Additionally, theproximal anchor 250 comprises a tether clamp 711 that may be used tolock or secure the tether 254 at a proximal location 715. During use,the first and second portions 702, 704 may slide away from each other(in the directions of arrows 706, 708) and toward each other, toaccommodate for variations in the length of tether extending from theskin surface. For example, in FIG. 7A, a relatively short amount of thetether 254 extends from the skin surface. However, as shown in FIG. 7B,when a greater length of the tether 254 extends from the skin surface,the proximal anchor 250 can accommodate for the difference withoutdecreasing the tension in the tether. Similarly, the length of thetether 254 extending from the skin surface may become shorter withoutresulting in breakage of the tether. While not shown, in some cases acover may be positioned over this proximal anchor 250 (e.g., to preventinterference from clothing, blankets, negative pressure wound therapy,or the like).

As discussed above, methods described herein employ expandable members15 to fill a fistula tract. Different expandable members 15 andarrangements thereof may be used with the devices, methods and kitsdescribed herein, as appropriate. FIG. 11 shows just one example of adevice body 13 comprising expandable members 15 coupled together with asuture 1100. Additionally, FIG. 12 shows a delivery catheter 280comprising a tubular member 1202 and expandable members 15 disposedwithin the tubular member 1202. The delivery catheter 280 may be used todeliver the expandable members 15 to a target site.

In some embodiments, the expandable members 15 of the device 5 maycomprise porous bodies. For example, the expandable members 15 maycomprise a compressed open cell polymer and may be made of any syntheticor natural biodegradable, resorbable, biocompatible polymer or polymers,such as collagen, hyaluronic acid and polyglycolic acid (“PGA”). Thebiodegradability may allow for degradation at a specified rate thatmatches the rate of tissue ingrowth and fistula tract healing, such thatby the time the fistula tract is healed, the material is completelyabsorbed by the body. It should be noted that in some cases, the fistulatract may heal before the material is completely absorbed by the body.That is, the degradation rate of the device may not match, or may beslower than, the rate of tissue ingrowth and fistula tract healing.

Expansion of the bodies 15 within the tract 10 provides a porousscaffold to the fistula tract and may partially or entirely stop theflow of bodily fluids through the tract. The scaffold provides a matrixthat may promote tissue in-growth, allowing the fistula to close. Incertain embodiments, one or more antimicrobial agents, such as silver,may be incorporated in the porous bodies 15 and/or in the insertionmethodology to actively prevent infection and/or sepsis formation andaid in the healing of the tract. The porous bodies 15 may includewound-healing agents, such as growth factors. In some embodiments, theporous bodies may include fibrosis-promoting agents.

A porous body may be adapted and configured to expand after placement inthe fistula tract and to absorb fluid, thereby approximating closely thetract intra-luminal walls. In some embodiments, a porous body mayinclude a porous resorbable open cell polymer foam adapted to expand andserve as a scaffold for tissue growth and closure of the fistula tract.

In certain embodiments, a porous body may comprise collapsed orcompressed pores, adapted and configured to increase in size afterplacement in a fistula tract, thereby filling the fistula tract. In someembodiments, the pores of the bodies may advantageously be of a reducedsize. For example, pore size may vary from 5 to 1000 microns with anoverall porosity of 25-95%. In certain embodiments, bodies with acontrolled pore size (i.e., without a broad distribution of pore sizes)of between approximately 50 microns and approximately 100 microns may beused. A body with a controlled pore size may promote greaterangiogenesis, which, in turn, may promote better wound-healing. Examplesof materials that may provide some or all of the controlled pore sizeand porosities include various biomaterials manufactured by Kensey NashCorporation, CollaPlug® or other collagen products as manufactured byIntegra Corporation, and STAR® materials as manufactured by HealionicsCorporation.

In some embodiments, the fluid permeability (i.e., porosity or poresize) of the bodies 15 may increase from the distal end of the device 5to the proximal end of the device 5. For example, a first body 15 at thedistal end of the device 5 may have a lower fluid permeability thanother bodies 15 of the device 5. That is, in a segmented body 13, a mostdistal body 15 or the most distal several bodies 15 (i.e., the singlebody 15 or the few multiple bodies 15 in closest proximity to the distalend of the tract, e.g., at the bowel end of the tract) may have thelowest fluid permeability and the bodies 15 extending proximally awayfrom the most distal body 15 may have a higher fluid permeability. Incertain embodiments, the fluid permeability of the bodies 15 proximal tothe most distal body or bodies 15 may increase from body to body, movingin the proximal direction. A most distal body 15 or bodies 15 with alowest fluid permeability may further enhance occlusion of the distalend 12 of the fistula tract 10 and prevent unwanted fluid from the bowelfrom entering the fistula tract. The bodies 15 proximal of the mostdistal body 15 or bodies 15 may have a higher fluid permeability topermit drainage of fluids accumulating in the tract and to promotetissue ingrowth to facilitate healing of the fistula tract.

A non-segmented body 13 may have a fluid permeability (i.e., porosity orpore size) that changes along its length. For example, the distalportion of the non-segmented body 13 may have a lower fluid permeabilityas compared to the proximal portion.

The porous bodies 15 may be in the form of polymer members that areanisotropic. For example, in some embodiments, the polymer members 15may be anisotropic such that they have substantial radial expansion, butminimal, if any, longitudinal expansion.

In certain embodiments, the porous bodies 15, when in a compressed ornon-expanded state, may have a volume that is significantly less thanthe volume of the bodies 15 when in a non-compressed or expanded state.For example, in some embodiments, the compressed or non-expanded volumeof the bodies 15 may be between approximately 10% and approximately 60%of the non-compressed or expanded state volume. In certain embodiments,the compressed volume may be between approximately 20% and approximately25% of the expanded volume. As a result, the bodies 15 may expandbetween approximately four and approximately five times their compressedvolumes when expanding from a compressed state to an expanded state. Forexample, a body 15 with a porosity of 80% can be compressed to 20% ofits expanded state. In other words, the body 15 may expand approximatelyfive times its compressed volume when expanding from a compressed to anon-compressed state. The body 15 may expand even more if it retains anyabsorbed fluid from the fistula tract 10.

The porous bodies 15, when in a compressed or non-expanded state, may berelatively easy to insert in a fistula tract 10 and may cause lessdamage upon insertion due to the reduced size. The compressed porousbodies 15 also may allow for controlled expansion. In other words, theexpanded size of a compressed porous body 15 is generally known and maybe chosen and optimized based upon the configuration of the fistulatract 10. Thus, use of a compressed porous body 15 may permit greaterocclusion of the fistula tract 10 because the compressed porous bodies15 conform to the tract 10, as opposed to making the tract 10 conform tothe body of the device. The porous bodies 15 also may not require fluidto expand or to be maintained in an expanded state. Such controlledexpansion porous bodies 15 may be formed of hyaluronic acid, hyaluronicacid mixed with collagen, or any other suitable materials that offercontrol or specific pore size or porosity.

In some embodiments, the controlled expansion of the bodies 15 may be afunction of precompressing the bodies 15 a certain extent (e.g.,approximately 80 percent of their non-compressed state) and thenreleasing the bodies 15 to resume their non-compressed state. Thus, itis possible to readily determine the final fully expanded condition ofthe bodies 15 because they may only expand to their non-compressed stateupon being released to resume the non-compressed state.

As mentioned above with respect to FIG. 1A, the porous bodies 15 of thedevice 5 may be operably connected by a connecting member 20. Theconnecting member 20 may be a bioresorbable and biocompatible filamentor string, for example. In certain embodiments, the connecting member 20may also be a filamentous string, which enables the decoupling of theplurality of porous bodies 15 from the connecting member subsequent toimplantation of the device 5 in the tract 10.

As shown above in FIGS. 1A and 1B, in some embodiments, the device 5 mayinclude at least two porous bodies 15. The bodies 15 may be adapted andconfigured to work together to form the device's overall body 13 andseparately to allow the device body 13 to conform to the tract 10 andfill all of the tract voids. In other words, the bodies 15 may beseparate individual bodies joined together via the connecting member 20along the length of the device 5, such that the resulting device body 13has a segmented configuration. In certain embodiments, when the bodies15 are in an expanded state or even in a non-expanded state, thespaced-apart distances D, D′ may be zero, such that the proximal anddistal ends 25, 30 of adjacent bodies 15 abut. In such an embodiment,the bodies 15 may appear to form a generally continuous porous devicebody 13 that is segmented by the interfaces of the adjacent proximal anddistal ends 25, 30 of adjacent bodies 15. Thus, regardless of themagnitude of the spaced-apart distances D, D′, in some embodiments, thedevice body 13 can be considered to be a chain or series of individualporous bodies 15 configured to work together and separately, resultingin an overall body 13 of the device 5 that is segmented and capable ofconforming to the tract 10. It should be noted that the device 5 doesnot stent open the tract 10, but rather, the device 5, when in anexpanded or non-compressed state, is capable of conforming to the tract10.

In some embodiments, the device 5 may be configured to fill multi-tractfistulas. For example, the device 5 may comprise multiple device bodies13 joined together at a common point of the device 5. In other words,the device may have at least two chains of porous bodies 15 joinedtogether to allow a segmented device body 13 to be inserted into each ofthe tracts 10 of a multi-tract fistula. Alternatively, at least twochains of porous bodies 15 may be joined together to create a device 5with at least two segmented device bodies 13.

In certain embodiments (not shown), the porous bodies 15 may alsoinclude attachment members that are configured to attach and engage thebodies 15 with the tract 10, and that deploy when the bodies 15 are in anon-compressed or expanded state. The attachment members may beunidirectional (e.g., comparable or similar to a fish hook barb) or mayhave a compressed fishbone-like structure and may be made of anyappropriate biocompatible, resorbable material. The attachment membersmay permit outward removal but not inward traction. That is, when theattachment members are deployed, the bodies 15 may be retracted towardsthe proximal end without damaging the fistula tract 10, but the bodies15 may be engaged with the tract 10 such that they will not migratetowards the distal end 12 of the tract 10.

As can be understood from FIG. 9B, in one embodiment, the device 5 maybe deployed from the lumen of a delivery sheath or catheter 900 via along, flexible rod or a “pusher” 903. The pusher 903 may be insertedthrough the delivery device 900 and may enable the clinician to push orotherwise direct the segmented device body 13 into the tract 10, therebyminimizing the dead space or void that may be left between theindividual segments of the device body 13 or between the body 13 andtract 10. In some embodiments, the porous bodies 15 may not be connectedvia a connecting member 20, but instead may be multiple free bodies 15that are inserted into the lumen of the sheath 900 for delivery into thetract. Thus, a pusher may enable the clinician to push or otherwisedirect the unconnected bodies 15 into the fistula tract 10.

In certain embodiments, the bodies 15 of the fistula closure device 5may be formed from materials other than a graft, wherein graft isdefined as a transplant from animal or human tissue.

In some embodiments, the bodies 15 of the fistula closure device 5 maybe formed from materials other than an extracellular matrix (“ECM”)material, wherein ECM material is defined as decellularized organictissue of human or animal origin. Furthermore, in some such embodiments,the bodies 15 of the fistula closure device 5 may be formed frommaterials other than those that are remodelable, where remodelable isdefined as the ability of the material to become a part of the tissue.Instead, in some embodiments, the bodies 15 of the fistula closuredevice 5 may rely heavily on the amount of induced cross-linking thatallows control of the resorption rate. Cross-linking essentiallydestroys the remodelable properties of a material. While remodelable maynot exclude resorbable material completely, in some embodiments, thebodies 15 of the fistula closure device 5 may be formed of material thatis completely resorbable and has no remodelable requirements orcapabilities.

In some embodiments of the fistula closure device 5, the device body 13may be formed of multiple bodies 15 to form a segmented body 13. Thebody 13 may include a distal occlusion member 200 (e.g., anumbrella-like member), the member 200 acting as an occlusion mechanismthat is more of an occlusive cover rather than a plug or sealing member.

The fistula closure devices 5 as described herein may be implanted intoa fistula tract 10 via various methods. For example, the fistula tract10 may be visualized via direct visual inspection or medical imagingmethods (e.g., Fluoroscopy, CT scan, MM, etc.). A guidewire may benegotiated through the tract 10. The tract 10 may then bede-epithelializing irrigated. The device 5 may then be threaded over theguidewire and pushed into the tract 10. The distal fistula opening 12may be occluded via elements of the device 5 (e.g., the most distal body110 and/or expandable member 200). The device 5 may be trimmed to thelength of the tract 10, after which the guidewire is removed. The device5 and, more specifically, the device body 13, may be irrigated to causeexpansion of the body 13. The device 5 may be anchored at the proximalfistula opening with a proximal end piece. For example, a retainingmember may be connected to the distal end of the device 5 and secured tothe region surrounding the proximal end opening of the tract 10, therebycreating tension in the device 5. The proximal fistula opening may thenbe covered with a dressing.

In another method of implanting the fistula closure device 5 in afistula tract 10, a compressed porous scaffold 13 is placed in thefistula tract 10, wherein the scaffold 13 is at least partially insertedinto the tract 10. The porous scaffold may be filled with, for example,an injectable polymer fluid, which may form an occlusive plug and maypromote tissue growth and hence healing of the fistula tract. The methodmay further include fixating the device 5 in the tract 10 using abiocompatible connecting member 20, such as a string, which is attachedto the device 5. The polymer injected into the tract 10 may be in a formthat allows the foam to approximate the walls of the fistula tract 10and fill any voids in the tract.

In another method of implanting the fistula closure device 5 in afistula tract 10, a distal end 32 of the device 5 may be placed in sucha way as to protect and occlude the distal end 12 of the fistula tract10. The body 13 of the device 5 may be inserted into the fistula tract10 in such a way as to at least partially fill the fistula tract 10. Thesurface load or point load dependent expansion of porous bodies 15 maythen be activated within the fistula tract and the device 5 may beanchored in place at the distal and/or proximal ends 32, 31. Forpurposes of this disclosure, surface load or point load dependentexpansion refers to the expansion of the porous bodies where, uponcontact between the fistula tract wall (the “load”) and a point on theporous body, that point of the porous body will stop expanding. Thepoints on any or all of the rest of the porous body will continue toexpand until the remaining points also make contact with the fistulatract wall. Thus, the surface load or point load dependent expansion ofthe bodies 15 of the device 5 disclosed herein allows the body 13 togenerally fill and conform to the tract 10 without distorting the tract10 or causing the tract to conform or deform due to the expansion of thebody 13 in the tract. This ability of the body 13 can be a result ofpre-compression of the body 13 and/or the nature of the material used.

Examples of materials from which to form the bodies 15 of the device 5include: AngioSeal-like products, collagen sponge or other biomaterialmaterials as manufactured by Kensey Nash Corporation (Exton, Pa.);CollaPlug® or other collagen products as manufactured by IntegraCorporation (Plainsboro, N.J.); and STAR® materials as manufactured byHealionics Corporation (Redmond, Wash.). With respect to the CollaPlug®material, in some embodiments, the CollaPlug® material may be compressedprior to delivery into the tract 10, the CollaPlug® material beingapproximately 90% porous. With respect to the STAR® materials, some suchmaterials are known to have a specific pore size that promotes betterangiogenesis. The STAR® materials and some of the materials and productsdiscussed above may be capable of achieving a desirable controlled poresize and overall porosity for purposes of the devices and methodsdisclosed herein.

In another method of implanting the fistula closure device 5 in afistula tract 10, the tract may be visualized and a guidewire may berouted into the tract. The tract 10 may be de-epithelialized andirrigated to remove any unwanted internal matter. The fistula closuredevice 5 may be tracked over the guidewire and the device 5 may then bereceived into the fistula tract until the distal end of the device 5extends beyond the distal fistula opening 12. The device 5 may beexpanded by irrigation so as to approximate the fistula tract 10. Thedevice 5 may be trimmed if required. The method may include clipping orotherwise securing the proximal end of the device 10 at the proximaltract opening to provide a secure anchor. The proximal opening may thenbe covered with a dressing. In one embodiment, the segmented body 13 ofthe device 5, when in an expanded state, generally approximates thevolume of the fistula tract with minimal distortion of the fistulatract.

FIGS. 13A-13C depict another example of a fistula closure device,comprising a generally disc-shaped sealing body 1302 having a proximalsurface 1304, a distal surface 1306 and an outer side wall 1308therebetween. To facilitate sealing of the fistula tract, the proximalsurface 1304 of the sealing body 1302 may comprise a seal 1310. In thedepicted example, the seal 1310 is located along the peripheral edge ofthe sealing body 1302, but in other examples may be spaced away from theedge. The seal 1310 depicted in FIG. 13A comprises an annularconfiguration, but in other examples, the seal may have a polygonal,oval, star or square shape, for example, that may be the same ordifferent shape as the sealing body 1302. The seal 1310 may be solid ormay comprise a hollow interior. In some instances, a hollow interior mayfacilitate collapse of the sealing body 1302 for delivery, or facilitatedeformation or conformation to the shape of a target location.

As further depicted in FIG. 13A, the sealing body 1302 may also compriseone or more ribs or support structures 1312. The number of supportstructures 1312 may be in the range of about one to about ten or more,from about two to about eight, about three to about six, or about fivesupport structures, for example. The support structures 1312 may beevenly or symmetrically spaced apart in a radial configuration withrespect to the center of the sealing body 1302 or a midline of thesealing body 1302. The support structures 1312 may also be solid orhollow. In some examples comprising at least one hollow supportstructure 1312 and a seal 1310 that is at least partially hollow, thesupport structure 1312 and the seal 1310 may be in fluid communicationthrough an access lumen 1314 provided on the sealing body 1302. Theaccess lumen 1314 may permit injection or filling of materials into thebody 1302, including but not limited to contrast agents (e.g. barium,contrast saline, etc.) or a bulking material such a silicone. The distalsurface 1306 may be generally smooth, which may facilitate passage ofmaterials through the gastrointestinal tract past the implanted sealingbody 1302, but in other examples may comprises one or more recesses,openings and/or projections. The proximal surface 1304 may compriserecesses 1316 located between the support structures 1312 and/or theannular seal 1310. In some embodiments, the recesses may reduce thedegree of surface contact between the sealing body 1302 and thesurrounding tissue, thereby shifting sealing forces along the annularseal 1310.

The sealing body 1302 may further comprise an attachment structure 1320to facilitate delivery of the sealing body 1302. The delivery catheter,if any, may releasably engage the sealing body 1302 at the attachmentstructure 1320. The attachment structure 1320 may also be the attachmentsite for one or more tethers or sutures that may be used in conjunctionwith the sealing body 1302. In some further examples, the attachmentstructure 1320 may be located centrally with respect to the overallshape of the sealing body 1302, but in other examples the attachmentstructure 1320 may be eccentrically located. The attachment structure1320 may be integrally formed with the access lumen 1314, or may beseparate from the access lumen, which may be used to inject materialsinto the hollow lumens and/or cavities of the support structures 1312and the annular seal 1310, if any. In other examples, through lumens inthe body may permit access to the intestinal lumen for fluid sampling,placement of sensors, and/or therapeutic agent delivery.

Referring to FIG. 14, the sealing body 1302 may be a distal portion of afistula closure device. In use, the sealing body 1302 may seal thefistula tract by tensioning the sealing body 1302 against the intestinalwall of a patient though one or more tethers 1424 and 1426 attached tothe sealing body 1302. The tethers 1424 and 1426 may be attached at theattachment structure 1320 or other location of the sealing body 1302,including but not limited to the annular seal 1310 and/or the supportstructures 1312. The multiple tethers 1424 and 1426 may be color codedto distinguish the various tethers during the implantation procedure. Atleast one of the tethers 1424 may be used to apply tension to thesealing body 1302 and seal the fistula tract. In some examples, a secondtether 1426 may be provided to as a guide element for delivery of theexpandable members. In some embodiments, providing separate tethers 1424and 1426 may reduce the risk of free-floating or unsecured expandablemembers 1428 should the tensioning tether 1424 rupture. FIG. 14, forexample, depicts the second tether 1426 that may be used to deploy oneor more expandable members 1428 along the fistula tract. At least one orboth of the tethers 1424 and 1426 may be secured using a proximalrestraining structure 1430 that resists distal sliding or displacementof the tether 1424 and/or 1426 by providing an increased surface area ortransverse dimension that resists collapse or entry of the restrainingstructure 1430 into the fistula tract.

It should be understood that features and characteristics describedherein with reference to specific expandable members 200 and sealingbodies 1302 may be applied to any of the other expandable members andsealing bodies described herein, as appropriate.

As shown in FIG. 14, the expandable members 1428 may comprise generallyelongate collagen plugs (or other biocompatible material) that areconfigured to expand, fill and conform to surrounding tissue structures.The plugs may have a generally cylindrical shape, but in alternativeexamples may have any of a variety of shapes, including spheres,rectangular blocks, conical or frusto-conical shapes, and the like. Notall of the plugs need to have the same size, shape, orientation and/orsymmetry. As further illustrated in FIG. 14, the expandable members 1428may be interconnected by a plug suture or tether 1432. The plug tether1432 may form a loop structure 1434 at one end of the plurality ofexpandable member 1428 that may facilitate delivery of the expandablemembers 1428 along at least one of the tethers 1426. The expandablemembers 1428 may be slidably attached or fixedly attached to the plugtether 1432 by a resistance interfit, but in other examples, one or moreexpandable members 1428 may have an enlarged tether lumen to facilitatesliding or other relative movement with respect to the plug tether 1432.In still other examples, one or more expandable members 1428 may beglued to the tether, or the plug tether 1432 may have a cross-overconfiguration or stitching through the expandable member to resistrelative movement or separation of the expandable member. For example,in some, all or at least the distalmost or free-floating expandablemember, the plug tether 1432 may be fixedly attached using any of avariety of attachment interfaces described above. In some furtherexamples, the plug tether 1432 may further comprise one or more knots orother fixedly attached structures along its length to limit sliding ormovement of an expandable member to a particular range.

In one exemplary delivery procedure, the fistula tract and surroundingarea may be prepped and draped in the usual sterile fashion. Anesthesiamay be achieved as needed using topical and/or injectable anesthetics.The fistula tract may then be irrigated with sterile saline, hydrogenperoxide or any other suitable biocompatible irrigation fluid. In somefurther examples, portions of the fistula tract may be de-epithelializedusing silver nitrate sticks, cautery and/or mechanical debridement usinga scalpel, for example. The delivery instrument may be removed from itsaseptic packaging and placed onto a sterile field. To reduce the risk ofdislodging the sealing body 1302, tensioning of the attached sutures1424 and 1426 may or may not contraindicated. Various extension tubesand stopcocks, if any, may be attached to the delivery instrument 1550at this time. Flushing, patency/leakage testing of the deliveryinstrument connections may be performed using saline or similar fluid.The integrity of the sealing body 1302 may also be assessed usingsaline, contrast agent or a mixture of both and the application ofpositive and/or negative fluid pressure through the delivery instrument1550. Prior to delivery, the sealing body 1302 may be evacuated withnegative pressure to collapse the sealing body 1302. The same or aseparate syringe of saline, contrast agent or combined fluid may beprepared as an inflation syringe for the sealing body.

The fistula tract may be traversed using a guidewire, with or withoutthe assistance of imaging modalities such as plain X-ray, fluoroscopy,CT scanning, endoscopy, or ultrasound, for example. The peel-away sheathmay be passed over the guidewire and through the dermal ostium of thefistula tract. A dilator may be used as needed to prepare the fistulatract for passage of the delivery instrument and/or endoscopicinstrument. The position of the sheath may be verified with the same ordifferent imaging modality. The procedure may be continued once thedesired sheath tip location is achieved or verified, e.g. the distal tipis located beyond the intestinal or central ostium of the fistula tract.The guidewire (and dilator, if any) may then be removed. The sheath maybe flushed with sterile saline. The collapsed sealing body 1302 may bewrapped around the distal end of the delivery instrument 1550 byrolling, rather than collapsing the sealing body 1302 like an umbrella.The delivery instrument 1550 may be inserted into the sheath andadvanced until the sealing body 1302 is located beyond the distal tip ofthe sheath. The relative location of the delivery instrument 1550 may beevaluated by imaging, by the distance between proximal ends of thesheath and delivery instrument, and/or by the loss of insertionresistance that may be tactilely felt once the sealing body 1302 hasexited the sheath. A 10 cc syringe, for example, may be attached to thedelivery instrument and negative pressure may be applied to the sealingbody 1302 through one of the stopcocks, which then may be closed tomaintain the sealing body 1302 in a collapsed state. The syringe maythen be removed and is replaced with a syringe of the same or smallersize. The stopcock is re-opened and the evacuation of the sealing body1302 may be confirmed by pulling back on the syringe and assessingplunger displacement. A portion of the fluid in the syringe (e.g. 0.5cc) may then be injected into the sealing body 1302 to inflate it. Thestopcock may be closed to maintain the inflation.

While maintaining the position of the delivery catheter (or the TouhyBorst valve), gentle traction may be applied to the tension tetherattached to the sealing body 1302 to fully seat the sealing body 1302 tothe delivery instrument 1550. The Touhy Borst valve may then be loosenedand the sheath may be partially retracted into the fistula tract (e.g.,proximal to the central ostium). The sealing body 1302 may then bedeployed by disengaging or otherwise separating the lock mechanismbetween the Touhy Borst valve 1562 and the connector 1556. The remainingdistal portions of the delivery instrument 1550 may then be slowlywithdrawn from the fistula tract. While maintaining slight tension onthe tension tether 1424 to hold the sealing body 1302 against thecentral ostium of the fistula tract, the sheath may be slid proximal thedesired length that is to be filled with the expandable members. Slighttension may be maintained on the tension tether 1424 through theremaining procedure until the tether is anchored to the skin.

The actuator 1572 may be inserted into the plug delivery catheter 1570until the suture loop 1434 just exits the distal end 1578 of thecatheter 1570. The actuator 1572 may then be withdrawn. Whilemaintaining slight tension on the tension tether 1424, the deliverytether 1426 may be threaded through the loop 1434 at the distal end 1578of the delivery catheter 1570. The catheter 1570 may then be advancedover the delivery tether 1426 until the catheter tip 1578 is located atthe desired delivery location. The actuator 1572 may be reinserted intothe catheter 1570 until the distal end 1574 of the actuator 1572contacts the most proximal expandable member 1428 in the catheter 1570.The position of the actuator 1572 may then be maintained while thedelivery catheter 1570 is retracted to deploy the distalmost expandablemember 1428. The catheter 1570 may or may not be relocated to deploy theremaining expandable members 1428. Once deployment of all the expandablemembers 1428 is completed, the Luer fittings on the proximal end 1576 ofthe delivery catheter 1570 and actuator 1572 may be engaged and thecatheter 1570 and actuator 1572 may be removed from the sheath. Salinemay be optionally infused through the sheath to facilitate expansion ofthe expandable members 1428. Using separately supplied catheters 1570and actuators 1572, additional expandable members may be deployed usingthe above procedure to fill the fistula to the desired level. Sealingbody 1302 placement may be reconfirmed by imaging techniques to ensurethat the sealing body 1302 is located against the central ostium.

While maintaining tension on the tension tether 1424, the restrainingstructure 1430 may be separated from the sheath and the sheath may beremoved from the fistula tract. While continuing to maintain slighttension on the tension tether 1424 through the restraining structure1430, the delivery tether 1426 may be sutured or otherwise attached tothe surrounding tissue using a free needle passed through therestraining structure and tied to the tissue with the desired tension.At a location opposing the delivery tether 1426 on the restrainingstructure 1430, a free needle may be used pass through the restrainingstructure 1430 and to suture the tension tether 1424 to the surroundingtissue. Additional sutures (e.g., 3-0 or 4-0 nylon) may be used tofurther secure the restraining structure 1430 to the surroundingsuperficial tissue as needed. Final imaging confirmation of the sealingbody 1302 placement along the central ostium may be performed at thispoint using the imaging modalities as previously described, but alsoincluding double-contrast x-ray studies and colonoscopy/enteroscopy. Anabsorbent dressing may be securely on top of the restraining structure1430 to absorb any excess drainage that may occur. Alternatively activedrainage of the fistula/wound may be performed using wound drainageproducts or negative pressure wound therapy products. Prophylacticantibiotics may be optionally provided post-procedure.

The size and shape of the restraining structure 1430 may be differentdepending upon the particular fistula being treated, but in someexamples, the restraining structure 1430 may have a diameter or maximumtransverse dimension that is at least the same as the sealing body 1302.In further examples, the diameter or maximum transverse dimension may beat least two times, three times, or four times or greater than thecorresponding dimension of the sealing body 1302. The restrainingstructure 1430 may also comprise one or more securing apertures 1436that may permit the attachment of the restraining structure 1430 to theskin or a bandage surrounding the dermal fistula opening. These securingapertures 1436 may be spaced around the periphery of the restrainingstructure 1430, closer to the outer edge rather than the center of therestraining structure 1430. In other examples, the restraining structure1430 may comprise an adhesive surface that contacts the skin surroundingthe fistula and resists movement. The tethers 1424 and 1426 of thedevice may be secured to the restraining structure 1430 by any of avariety of mechanisms, including a clamping structure, adhesive, or by adeformable slit 1438 that provides a releasable friction fit interfacefor the tethers 1424 and 1426. The attachment site of the tethers 1424and 1426 on the restraining structure 1430 may further comprise accessopenings 1440 that may be used to infuse therapeutic agents into thefistula, and/or to permit passive or active fistula drainage, or theapplication of negative pressure therapy to the fistula. FIG. 15Adepicts the restraining structure 1430 without the attached tethers.

Referring to FIG. 15B, positioning of the sealing body 1302 and tethers1424 and 1426 may be performed using a delivery instrument 1550 thatcomprises an elongate tubular element 1552 that is configured with adistal end 1554 that releasably attaches to the attachment structure1320 of the sealing body 1302. The interface between the attachmentstructure 1320 and the tubular element 1552 may comprise a resistanceinterfit, but may alternatively comprise a mechanical interlocking fitsuch as a helical threaded interface, for example. In some embodiments,attachment of the sealing body 1302 to the tubular element 1552 may alsobe provided by tensioning the tether 1424 that passes through thetubular element 1552 and other portions of the delivery instrument 1550.To prepare the sealing body 1302 for delivery, the sealing body 1302 maybe collapsed or compressed around the distal end 1554 of the tubularelement 1552 and held in that configuration using a cannula orintroducer. In some examples, applying suction or a vacuum mayfacilitate collapse of the sealing body 1302. Although delivery of thesealing body 1302 may be performed through the fistula tract and towardthe gastrointestinal site, in other examples, the cannula or introducermay be configured to pierce tissue so that delivery instrument 1550 maybe used to deliver the sealing body 1302 and at least one tether 1424along a secondary tract other than the fistula tract. This secondarytract may be a pre-existing tract or a tract formed by the insertiondelivery instrument.

As shown in FIG. 15B, other features of the delivery instrument 1550 mayinclude one or more connectors 1556, 1564 that permit the attachment oruse of access lines 1558 and stopcocks 1560, 1566, for example, whichmay facilitate the aspiration or infusion of materials, or the insertionof endoscopic tools or sensors during the delivery procedure. Thedelivery instrument 1550 may include a hemostasis valve 1562 or otherfluid-sealed interface that permits passage of items such as the tether1424 while resisting fluid leakage.

The expandable members 1428 may be provided in a rigid or flexibletubular catheter 1570, as depicted in FIG. 15D. To expel or release theexpandable members 1428, a push element or actuator 1572, depicted inFIG. 15C, may be used to serially release the expandable members 1428from the distal end 1578 of the catheter 1570. This may be performed bypushing the distal tip 1574 of the actuator 1572 through the proximalend 1576 of the catheter 1570 while holding the catheter 1570 in place,or by holding the actuator 1572 in place while withdrawing the catheter1570, for example.

To perform the procedures described above, a kit may be provided thatcontains the delivery instrument 1550 along with the sealing body 1302and attached tethers 1424 and 1426. The sealing body 1302 and attachedtethers 1424 and 1426 may be coupled to the instrument 1550 at thepoint-of-manufacture or at the point-of-use, and therefore may beprovided in the kit either pre-attached or separate from the instrument1550. The kit may also comprise an actuator pre-filled catheter 1570with one or more expandable members 1428 that are pre-attached with aplug tether 1430. Additional catheters 1570 with expandable members 1428may be also be packaged and provided separately. In further examples,the kit may also contain one or more other items, including but notlimited to a guidewire (e.g. 0.038″ guidewire), a peel-away sheath (e.g.7F, 8F, 9F, 10F, or 12F sheath), one or more syringes (e.g. 0.5 cc, 1cc, 5 cc, and/or 10 cc syringes), saline or biocompatible fluid,contrast media, a scalpel, one or more free needles, and non-resorbablesutures (e.g. 3-0 or 4-0 nylon suture) that may be used to attach therestraining structure 1430 to the adjacent skin or to a bandage. Afistula tract dilator may also be provided in the kit.

Fistula treatment devices described herein may in some cases be providedin a kit. The kit may also include any other appropriate devices orcomponents, such as delivery tools or other fistula treatment devices(i.e., a kit may include multiple fistula treatment devices). Thecontents of a kit may be provided in sterile packages. Instructions maybe provided on or with the kit, or alternatively via the internet oranother indirect method, and may provide direction on how to employ thekit (e.g., outlining a deployment method such as one of those describedherein).

FIG. depicts an exemplary kit 800. As shown there, the variouscomponents of the fistula closure device 5 are provided in a sterilepackage 802. For example, the sterile package 802 may contain theconnecting member 20, the expandable member or distal anchor 200, theproximal anchor 250, and individual porous bodies 15 for threading overthe connecting member 20. Instructions 804, which may be provided on orwith the kit 800, or alternatively via the internet or another indirectmethod, provide direction on how to employ the kit. The instructionsmay, for example, outline a deployment method similar to those describedabove. It should be understood that the concept of kits may readily beapplied to any of the devices and device components disclosed herein, asappropriate.

FIGS. 16A and 16B depict another example of a distal anchor 1600 foroccluding a distal opening of fistula tract. As depicted therein, distalanchor 1600 may comprise a plurality of foldable members 1602, 1604,1606, and 1608 threaded on a suture 1610. FIGS. 16A and 16B illustrate,respectively, an expanded and a restrained configuration of distalanchor 1600. The expanded configuration illustrated in FIG. 16A mayrepresent the configuration of the distal anchor 1600 when it has beenreleased from an insertion device into a body lumen. The restrainedconfiguration illustrated in FIG. 16B may represent the configuration ofthe distal anchor when a restraining force is exerted on the distalanchor 1600 by tensioning the suture 1610 while the distal anchor 1600is positioned over a distal opening of a fistula tract. As can beappreciated by comparing FIGS. 16A and 16B, flexible members 1604, 1606,and 1608 are configured to slide along suture 1610. Proximal-mostfoldable member 1608 may be further configured to occlude a distalopening of the fistula tract. Distal-most foldable member 1602 may beconfigured to reduce or prevent rupturing at the center of foldablemember 1608 when the suture 1610 is tensioned during positioning of thedistal anchor 1600. Distal-most foldable member 1602 may be configuredto a size and shape that distributes the force exerted by the sutureover a wider area—the area of contact between foldable member 1602 andthe next foldable member, first inner foldable member 1604. In this way,pressure exerted on foldable member 1608 by tensioning suture 1610 canbe reduced. Inner foldable members 1604 and 1606 may also serve toreduce or prevent rupturing of the proximal-most foldable member 1608 byfurther distributing the force exerted on foldable member 1608.Distal-most foldable member 1602 may also comprise a suture attachmentstructure 1612 for attaching suture 1610.

Each foldable member comprises a large dimension (diameter) and a smalldimension (thickness). In some variations, the diameter is considerablylarger than the thickness. For example, the foldable members of distalanchor 1600 comprise a very large diameter relative to their thicknessso that the foldable members take on a “pancake” appearance. In somevariations, the small dimension of the foldable members arecharacterized as percentages of the large dimension, and may sometimesbe less than or equal to 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 15%,20%, 30%, 40% or 50%, or any percentage range between any two of theabove percentages. The foldable members are configured so that the largedimension is oriented generally in parallel to a surface of a body lumenwhen the foldable members are deployed.

In some variations, the foldable members may reduce in diameter from theproximal-most foldable member 1608 to the distal-most foldable member1602. The diameter of the distal-most foldable member may becharacterized as a percentage from 1% to 100% of the diameter of theproximal-most foldable member 1602, and may sometimes be about 5%, 10%,20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%,90%, or 95%, or any percentage range between any two of the abovepercentages. In other variations, the diameter difference may beapproximately equal to a percentage between any of the foregoingpercentages. The diameters of the inner foldable members 1604 and 1606may also be characterized as a percentage from 1% to 100% of thediameter of the proximal-most foldable member 1602, and may sometimes beabout 5%, 10%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%,75%, 80%, 85%, 90%, or 95%, or any percentage range between any two ofthe above percentages. In other variations, the diameter difference maybe approximately equal to a percentage between any of the foregoingpercentages. In some variations, the diameter of the proximal-mostfoldable member may be sized to occlude a distal opening of a fistulatract. In some variations, the diameter of the proximal-most foldablemember may be in the range of about 4 mm to about 50 mm, sometimes about8 mm to about 30 mm, and other times about 10 mm to about 45 mm, andstill other times about 12 mm to about 30 mm. Further, although fourfoldable members are illustrated in FIGS. 16A and 16B, other variationsmay include any number of foldable members, including 2, 3, 5, 6, 7, 8,9, 10 foldable members.

In some variations, one or more of the foldable members arenon-circular. A non-circular outline can be understood to be any shapein which the perimeter is not a constant radius from a center point.Non-circular shapes include shapes with first-derivative discontinuitiesat one or more locations. Non-circular shapes may also be Non-circularshapes may also be Non-circular shapes a generally circular shape withprotrusions or recesses on the perimeter to accommodate a predeterminedsurface of a body lumen. Non-circular shapes may include, but are notlimited to, ovals, ellipses, rectangles, lenses, deltoids, andbell-shapes. When non-circular, a diameter of a foldable member may beunderstood to mean a length of the member in one dimension. For example,a line taken through a center point or a widest span of the member. Insuch variations, the diameters of the distal-most and inner foldablemembers may be characterized as a percentage from 1% to 100% of thediameter of the proximal-most foldable member, and may sometimes beabout 5%, 10%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%,75%, 80%, 85%, 90%, or 95%, or any percentage range between any two ofthe above percentages. In some variations, some of the foldable memberstake a shape different from one or more of the other foldable members.For example the distal members may be circular, but the proximal-mostfoldable member may be shaped to occlude a non-circular fistula opening.In some other variations, the distal foldable members are alsonon-circular in order to achieve a desired distribution of forces, forexample.

Suture attachment structure 1612 is illustrated on a distal surface offoldable member 1602, but in some variations is positioned on a proximalsurface of distal-most foldable member 1602. When on the distal surface,the suture attachment structure may comprise an aperture to allow thesuture to pass through the foldable member and an additional feature tofixedly couple the suture to the foldable member. When positioned on theproximal surface, the suture attachment structure may include a loop orother feature to fixedly couple the suture to the foldable member. Insome variations, the suture attachment structure includes a recess onthe distal surface of the distal-most foldable member 1602. Distal-mostfoldable member 1602 may also comprise reinforcing structure (not shown)for the suture attachment structure 1612. In some variations, thereinforcing structure is a wire mesh embedded within distal-mostfoldable member 1602 and configured to distribute the force resultingfrom tensioning the suture across all or some of the distal-mostfoldable member 1602. In other variations, the reinforcing structuremight include a button-shaped suture attachment structure, wherein theexpanded areas of the button-shaped suture attachment structure serve todistribute the force over a wider area.

In some variations, the foldable members 1604, 1606, and 1608 mayinclude apertures (not shown) to permit the members to slide alongsuture 1610. Although illustrated in FIGS. 16A and 16B as passingthrough the center of the foldable members, in some variations thesuture does not pass through the centers of one or more foldablemembers. For example, when the surface of a distal opening of a fistulatract does not lie in a plane orthogonal to the axis of the fistulatract, tensioning of the suture may cause an unequal distribution offorce on the proximal-most disk. In such a scenario, the apertures maybe off-center to redistribute the forces to provide an even, reducedpressure on the proximal-most foldable member. In some variations, theapertures may be reinforced by a ring or grommet. The reinforcementstructure, if any, may be fully embedded with the foldable member, ormay be partially exposed on either the distal and/or proximal surface ofthe member. In some further variations, the reinforcement structure mayalso comprise an interlocking structure to interlock with acomplementary interlocking structure of the reinforcement structure ofan adjacent foldable member. Other examples of inter-member lockingfeatures are described below.

As described above, the foldable members 1602, 1604, 1606, and 1608 areconfigured to be released from an insertion device. In some variations,the foldable members are configured to be reduced in size to fit withinan insertion rod of a given diameter. For example, one or more of thefoldable members may be configured to reduce its cross-sectional profileby folding or rolling, thereby facilitating entry into the insertionrod, as described in more detail later. In some variations, theflexibility of the foldable members may be increased as the diametersincrease to facilitate folding or rolling of the foldable members to apredetermined cross-sectional profile for insertion. In some variations,a flexibility of a foldable member may be characterized by a thicknessof the foldable member. In some variations, a flexibility of thefoldable members may be characterized by its percentage thickness, from1% to 100%, of the thickness of the distal-most foldable member, and maysometimes be about 5%, 10%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%,65%, 70%, 75%, 80%, 85%, 90%, or 95%, or any percentage range betweenany two of the above percentages. In some variations, a flexibility ofthe foldable members may be characterized by its percentage density,from 1% to 100%, of the density of the distal-most foldable member, andmay sometimes be about 5%, 10%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%,60%, 65%, 70%, 75%, 80%, 85%, 90%, or 95%, or any range between any ofthe two percentages. In some variations, a flexibility of the foldablemembers may be characterized by its percentage coefficient of resistanceto deformation, from 1% to 100%, of the coefficient of resistance todeformation of the distal-most foldable member, and may sometimes beabout 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, or 95%, or anypercentage range between any two of the above percentages. In somevariations, the flexibility of a foldable member may be constant acrossthe member. In other variations, the flexibility of a foldable membermay vary across the member by, for example, a variance in the densityand/or thickness in different regions of the foldable member. Thisflexibility variance may be controlled to facilitate folding the memberor to facilitate coupling two foldable members.

Foldable members 1602, 1604, 1606, and 1608 are depicted in FIGS. 16Aand 16B as generally planar. In some variations, the foldable membersare non-planar. For example, the foldable members may be generallyconcave. A concave geometry may advantageously distribute pressure in apredetermined field when the foldable members are fully restrained. Agenerally concave shape may also reduce the propensity of the distalanchor to pucker and result in a central region of the distal anchorlying proximal to an outer region when the distal anchor is in thedeployed configuration. When the distal anchor is in the deployedconfiguration, a relatively large quantity of pressure may focus in thecentral region of the distal anchor, possibly resulting in a structuralfracturing of the distal anchor at the central region. A concavegeometry may also advantageously limit the distal anchor's re-entry intothe fistula tract as a result of puckering, that is, may limit thepropensity of a central region of the distal anchor to lie proximal toan outer region when the distal anchor is fully restrained. Thegenerally concave geometry of the foldable members may be characterizedby a cross-sectional curve with a zero first derivative when thefoldable member is rotated 90 degrees clockwise (that is, when thefoldable member is turned on its side). When rotated back 90 degreesanti-clockwise, the zero first derivative may be located at aproximal-most or distal-most point of the curve. FIGS. 17A and 17Billustrate side views of two exemplary sets 1700 and 1720, respectively,of generally concave foldable members with zero first derivatives at theproximal-most and distal-most points of the curve, respectively. FIG.17A depicts a side-view of a set 1700 of foldable members 1702, 1704,1706, and 1708 with zero first derivatives located at the proximal-mostpoint of the curves, that is, the geometry of the cross-sections of thefoldable members forms a reverse “C.” Foldable members 1702, 1704, 1706,and 1708 are slidably connected by suture 1710. FIG. 17B depicts aside-view of a set 1720 of foldable members 1722, 1724, 1726, and 1728with zero-derivatives located at the distal-most point of the curves,that is, the geometry of the cross-section foldable members forms a “C.”Foldable members 1722, 1724, 1726, and 1728 are slidably connected bysuture 1730. Although each foldable member depicted in FIGS. 17A and 17Bcomprises a constant radius of curvature, some variations may includeone or more foldable members with a non-constant radius of curvature.Such shapes may include, but are not limited to, a bell, a cone, amushroom head, or a box. In some variations, the geometry of a foldablemember may be characterized as a 180 degree revolution of a curve abouta line through a point of zero first derivative. For example, thegeometries illustrated in FIGS. 17A and 17B may be generated by rotatingan arc of fixed radius about its minimum point of zero first derivative.In other variations, the geometry may be defined by rotating a paraboliccurve about a point of zero first derivative, wherein a parabolic curveis defined by the equation y=Cx², where (x, y) comprise a range in aCartesian plane and C is any real, non-zero number. In other variations,the geometry may be defined by a rotating the two-dimensional polynomialequation y=Σa_(n)x^(n), where (x, y) comprise a range in a Cartesianplane, a_(n) is any real number, and n is any integer.

Although the geometries described above are generated by a single curvedefining both the distal and proximal surface of each foldablemember—that is, the foldable member has a constant thickness—othervariations may have different curves to respectively define the proximaland distal surfaces. Further, although the curves above are discussedwith respect to an (x,y) Cartesian plane, it should be understood thatthe cross-section of the foldable member may not be positioned in afistula tract so that the curve remains in that orientation. Forexample, although a cross-sectional area of a foldable member may bedescribed in (x,y) coordinates so that its first derivatives are at thetop or bottom of a curve, in some variations, the foldable member isrotated for insertion so that the minimum point is now at a verticalmid-point.

Further, the curves and shapes described above refer to a general oroverall shape of a foldable member, the foldable members may haveadditional surfaces features. For example, a foldable member's overallshape may be augmented with any of the recesses, protrusions, andcoupling members described herein.

As depicted in FIGS. 17A and 17B, the relative curvature of the foldablemembers increases from the proximal-most foldable member to thedistal-most foldable member, that is, the radius of curvature decreasesfrom the proximal-most foldable member to the distal-most foldablemember. In some variations, the radius of curvature of the distal-mostfoldable member and inner foldable members may be characterized as apercentage, from 1% to 100%, of the radius of curvature of theproximal-most foldable member, and may sometimes be about 5%, 10%, 20%,30%, 40%, 50%, 60%, 70%, 80%, 90%, or 95%, or any percentage rangebetween any two of the above percentages. In some variations, thecurvature decreases from the proximal-most foldable member to thedistal-most foldable member, that is, the radius of curvature increasesfrom the proximal-most foldable member to the distal-most foldablemember. In some variations, the radius of curvature of the proximal-mostfoldable member and inner foldable members may be characterized as apercentage, from 1% to 100%, of the radius of curvature of thedistal-most foldable member, and may sometimes be about 5%, 10%, 20%,30%, 40%, 50%, 60%, 70%, 80%, 90%, or 95%, or any percentage rangebetween any two of the above percentages. In other variations, thecurvature of the members may be constant. A variation in curvature amongthe foldable members may be determined to account for a variation inflexibility among the foldable members. For example, a less flexiblemember may be more likely to resist deformation when fully restrainedand so less curvature may be necessary. A variation in curvature amongthe foldable members may also be determined to account for a variationin pressure exerted on the foldable members in the restrained configuredand its effect on each foldable member's relative deformation. Forexample, a more distal foldable member is likely to deform more due tothe pressure being exerted more directly on that member. In somevariations, the unrestrained curvature of each foldable member may bedetermined to generate a predetermined shape of the distal anchor in therestrained configuration. That is, the curvature of the unrestrainedfoldable members may be determined so that a predetermined shape isachieved once all the foldable members are restrained and coupled toeach other. In some variations, the predetermined shape is planar. Inothers, the predetermined shape is non-planar. In some variations, thecurve may be a bell-shape curve so that the revolved curve may includeoutside edges with a lower curvature than a central region. In othervariations, the curve may include outside edges with a higher curvaturethan a central region. Also, although the exemplary embodiments depictedherein comprise multi-member distal anchors that generally comprise areduced member size from proximal to distal, in other variations, themembers may be generally of the same size, and may or may not vary incurvature from proximal to distal, as described above.

Returning to FIGS. 16A and 16B, foldable members 1602, 1604, 1606, and1608 are depicted as being generally smooth on their distal faces. Insome variations, one or more foldable members include additionalfeatures to restrict relative movement of the foldable members in adirection generally transverse to the direction of the force exerted bythe suture. In some variations, movement is restricted by surfacefeatures on one or more foldable members that fixedly couple the one ormore foldable members to adjacent foldable members. In other variations,a pair of adjacent foldable members include electromagnetic elementsthat produce attractive electromagnetic forces, such as opposingmagnetic poles, that fixedly couple the adjacent foldable members. Inother variations, an adhesive may be used to fixedly couple the one ormore foldable members to adjacent foldable members. For example, onesurface of a foldable member may include an adhesive or complementaryinterconnecting structures, including but not limited to hook-and-loopattachment structures. In some variations, one surface of a foldablemember may comprise a curing agent. In yet further variations, thecuring agent may be enclosed in one or more capsules, where the capsuleis configured to rupture open exposure to an agent included on theopposing surface of the adjacent foldable member. In other variations,the capsule may rupture as a result of the pressure exerted when thedistal anchor is restrained by a suture.

In some variations, the proximal surface of the proximal-most foldablemember may be structured to facilitate a secure and lasting coupling ofthe distal anchor to the surface of a body lumen. In some variations,the structure may be a grapple, as described herein. In some variations,an adhesive may be added to the proximal surface of the proximal-mostmember. The adhesive may be applied by a physician before inserting theproximal-most foldable member into the body lumen or applied afterinsertion. In other variations, the adhesive may be applied during amanufacturing process and covered with a liner. In some variations, theliner is removed by the physician prior to insertion. In othervariations, the liner is configured to dissolve upon contact with bodilyfluid or after a force is applied to the distal anchor. The adhesive mayinitially strengthen the bond of the proximal-most foldable member tothe tissue and then gradually degrade in strength as fistula tracthealing occurs or after fistula tract healing. Depending on thevariation, the adhesive may create a fluid impermeable seal for at least7, 14, 21, 28, 35, 60 or any other number of days. The structure for asecure and lasting coupling may also comprise microneedles, such ashooks and/or barbs. The microneedles may be distributed throughout theproximal surface of the proximal-most member, but may also bedistributed at predetermined locations. In some variations, themicroneedles are distributed along a perimeter of the proximal surface,but in other variations the microneedles may be distributed at aposition where contact is anticipated, such as the inner sealing regionsdescribed herein.

In some variations, a drug-eluting or therapeutic agent may be added tothe distal anchor or the suture associated therewith. The drug-elutingor therapeutic agent may include healing factors, antibiotics, or otherhealing agents, for example. In some variations, the drug-eluting agentis coated on a foldable member or a suture. In other variations, thetherapeutic agent is impregnated within a foldable member or a sutureand may be configured for latent release.

In some variations, one or more of the foldable members or the suturemay comprise a radio-opaque material or radio-opaque markers. In thisway, the distal anchor or suture can be viewed in vivo by using anX-ray, CT scanner, or similar imaging devices.

FIGS. 18 to 24 depict cross-sectional views of exemplary topographicalfeatures for coupling adjacent foldable members. FIG. 18 depicts across-sectional view of distal anchor 1800 comprising foldable members1802, 1804, 1806, and 1808 in the deployed configuration. Thecross-sectional profile of each foldable member can be characterized ashaving two dimensions, a width dimension (horizontal dimension as viewedin FIG. 18) and a height dimension (vertical dimension as viewed in FIG.18). The foldable members are configured to generally orient the widthdimension of the distal anchor 1800 in parallel with the surface of abody lumen when the distal anchor is in the restrained configuration.Each of the foldable members 1802, 1804, 1806, and 1808 includetopographical features configured to restrain relative movement of thefoldable members in a direction parallel to the width of the foldablemember. In this way, distal anchor 1800 may be rigidly coupled to thesurface of the body lumen.

A proximal surface of each of the distal-most foldable member 1802,first inner foldable member 1804, and second inner foldable member 1806is contoured to receive a distal surface of the first inner foldablemember 1804, second inner foldable member 1806, and proximal-mostfoldable member 1808, respectively. The surface contours of each of thefoldable members serve to relatively restrain the foldable members inthe width dimension. Because the cross-sectional view shown in FIG. 18is at least partially revolved about an axis generally oriented in theheight dimension, the surface contours of each of the foldable membersserve to relatively restrain the foldable members in a plane orthogonalto the height dimension. Further, because a suture restrains thefoldable members in the height dimension, the foldable members of thedistal anchor 1800 is relatively restrained in three orthogonaldimensions, thereby securely holding the distal anchor in position onthe surface of a body lumen at the distal opening of a fistula tract.

Proximal-most foldable member 1808 may be generally described as havingan inner region 1810 and an outer region 1812 on its distal surface.Inner region 1810 may be defined as a generally smooth surface, such asa surface with a constant radius of curvature. Outer region 1812 may bedefined as beginning at a point at which the constant radius ofcurvature ends—such as the angular region 1818 identified in FIG. 18—andcontinuing until the peripheral edge of foldable member 1808. Outerregion 1812 may be a distal protrusion 1814 and inner region 1810 may bea recess, such as depicted in FIG. 18. In other variations, an innerregion is a distal protrusion and an outer region is a recess. Theproximal surface of the foldable member adjacent to the proximal-mostfoldable member may be contoured to relatively restrain the adjacentfoldable member. For example, second inner foldable member 1806comprises a proximally protruding inner region and a recessed outerregion, as depicted in FIG. 18.

Distal protrusion 1814 of proximal-most foldable member 1808 restrainsthe second inner foldable member 1806 in the width dimension. Protrusion1814 may be characterized by angular region 1816, angular region 1818,angular region 1820, and the length of the sides 1822 and 1824connecting angular region 1816 to angular region 1820 and angular region1820 to angular region 1818, respectively. Angular region 1816 may becharacterized as the angle between a proximal surface of theproximal-most foldable member 1808 and the side 1822 of theproximal-most foldable member 1808. In some variations, this angle maybe any angle between 0 and 90 degrees, including 0°, 10°, 20°, 30°, 40°,50°, 60°, 70°, 80°, and 90°, or any range between any two of the aboveangles. Angular region 1818 may be characterized as the angle betweenthe side 1824 of the proximal-most foldable member 1808 and the surfaceof the inner region 1810 of the proximal-most foldable member 1808. Insome variations, this angle may be any angle between 180 and 270degrees, including 180°, 190°, 200°, 210°, 220°, 230°, 240°, 250°, 260°,and 270°, or any range between any two of the above angles. In somefurther variations, angular region 1818 may include an angle greaterthan 270 degrees to provide a “snap-fit” with an opposing surface of anadjacent foldable member. Angular region 1820 may be characterized asthe angle between the side 1822 of the proximal-most foldable member1808 and the side 1824 of the proximal-most foldable member 1808. Insome variations, this angle may be any angle between 0 and 180 degrees,including 0°, 10°, 20°, 30°, 40°, 50°, 60°, 70°, 80°, 90°, 100°, 110°,120°, 130°, 140°, 150°, 160°, 170°, and 180°, or any range between anytwo of the above angles. Although angles 1816, 1818, and 1820 aredepicted in FIG. 18 as sharp corners, other variations may includefilleted or rounded angles. Sides 1822 and 1824 may be linear ornon-linear. For example, side 1822 may be curved where side 1824 may beflat. In other variations, side 1822 may be flat and side 1824 may becurved. In yet other variations, sides 1822 and 1824 may be both curvedor both flat. Sides 1822 and 1824 may be characterized as a percentageof the width of the proximal-most foldable member 1808 and may sometimesbe about 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, or 95%, or anypercentage range between any two of the above percentages.

The relative widths of the inner regions and outer regions may bevaried. In some variations, the width of the inner region ischaracterized as a percentage of the width of the outer region and maysometimes be about 5%, 10%, 20%, 30%, 40%, 45%, 50%, 60%, 70%, 80%, 90%,or 95%, or any percentage range between any two of the abovepercentages. In some variations, the width of the outer region ischaracterized as a percentage of the width of the inner region and maysometimes be about 5%, 10%, 20%, 30%, 40%, 45%, 50%, 60%, 70%, 80%, 90%,or 95%, or any percentage range between any two of the abovepercentages.

Proximal-most folding member 1808 is depicted as comprising an innerregion which is relatively thin with respect to the total thickness ofthe distal anchor 1800 in the constrained configuration. In somevariations, the thickness of the inner region is characterized as apercentage of the thickness of the distal anchor 1800 in the constrainedconfiguration and may sometimes be about 5%, 10%, 20%, 30%, 40%, 45%,50%, 60%, 70%, 80%, 90%, or 95%, or any percentage range between any twoof the above percentages.

Proximal-most foldable member 1808 is illustrated as comprising agenerally concave proximal surface with a constant radius of curvature.In other variations, the proximal surface of proximal-most foldablemember 1808 has a non-constant radius of curvature. In yet other,variations the proximal surface of proximal-most foldable member 1808comprises any of the surface geometries described herein. In somevariations, the proximal surface of proximal-most foldable member 1808is contoured to improve alignment with a non-planar surface of a bodylumen.

In some variations, the cross-sectional profile of the foldable membersillustrated in FIG. 18 is rotated 180 degrees to generate thethree-dimensional geometry of the foldable members. That is, thecross-sectional profile illustrated in FIG. 18 may be representative ofany cross-sectional profile taken through a center point of the foldablemembers. In other variations, the profile is not rotated 180 degrees,that is, the foldable member may not comprise the same cross-sectionalprofile taken through a center point of the foldable member at everyangle. For example, the cross-sectional profile illustrated in FIG. 18may be repeated for a first range of degrees and then a differentcross-sectional profile repeated for a second range of degrees. Forexample, the cross-sectional profile for the first range may be thatdepicted in FIG. 18 where the cross-sectional profile for the secondrange may be generally smooth. This patterning may better facilitatefolding of the foldable members, while still relatively restraining thefoldable members. In some variations, the first range is larger than thesecond range.

The second inner foldable member 1806 may comprise a proximal surfacethat is contoured to align exactly with the contours of the distalsurface of proximal-most foldable member 1808. In some variations, thesurfaces do not align exactly and may be contoured only as is necessaryto provide a predetermined limit on relative movement between thefoldable members in the transverse direction. As depicted in FIG. 18,the proximal surface of the second foldable member 1806 has a similargeometry to the proximal surface of the proximal-most foldable member1808. In other variations, the proximal surface of the second innerfoldable member 1806 has a dissimilar geometry to the proximal surfaceof the proximal-most foldable member 1808. Further, although the innerand outer regions of the second foldable member 1806 have similar widthsto the inner and outer regions of the proximal-most foldable member,other variations may have dissimilar widths. Likewise, although theangles on the distal surface of the second inner foldable member 1806are similar to the angles on the distal surface of the proximal-mostfoldable member 1808, other variations have dissimilar angles as thoseon the distal surface of the proximal-most foldable member 1808. Anyangular features on first inner foldable member 1804 may take any of theangles described above with respect to proximal-most foldable member1808. Similarly, any inner and outer regions of inner foldable membermay take any of the relative thickness described above with respect toproximal-most foldable member 1808.

Additional inner foldable members may take similar structures andprovide similar functions as those described above with respect tosecond inner foldable member 1806. For example, first inner foldablemember 1804 may comprise a proximal surface configured to align exactlywith the contours of the distal surface of second inner foldable member1806, but other variations may not align the opposing surfaces exactly.Any angular features on second inner foldable member 1806 may take anyof the angles described above with respect to proximal-most foldablemember 1808. Similarly, any inner and outer regions of first innerfoldable member 1804 may take any of the relative widths described abovewith respect to proximal-most foldable member 1808.

Similarly, the proximal surface of distal-most foldable member 1802 maytake similar structures and provide similar functions as those describedabove with respect to the proximal-most foldable member 1808 and theinner foldable members 1804 and 1806. Any angular features ondistal-most foldable member 1802 may take any of the angles describedabove with respect to the inner foldable member 1804 and 1806.Similarly, any inner and outer regions of distal-most foldable member1802 may take any of the relative thickness described above with respectto proximal-most foldable member 1808.

Distal-most foldable member 1802 may be concave on its distal surface,as depicted in FIG. 18. In some variations, the distal surface ofdistal-most foldable member 1802 is not concave. In particular, thedistal surface of the distal-most foldable member is not constrained byan interaction with the surface of a distally adjacent foldable member.Accordingly, the distal surface of distal-most foldable member 1802 maybe smooth to prevent any lodging of external elements, such as partiallydigested foot particles. In some variations, the distal surface ofdistal-most foldable member 1802 may take a form that facilitatesfolding of foldable member prior to deployment. In some variations, thedistal surface of distal-most foldable member 1802 comprises a sutureattachment structure. In further variations, the suture attachmentstructure may include reinforcement structure 1826. Reinforcingstructure 1826 may be a wire mesh embedded within distal-most foldablemember 1802 and configured to distribute the force resulting fromtensioning the suture across all or some of distal-most foldable member1802, thereby reducing the risk of rupturing the foldable member. Inother variations, the reinforcing structure might include abutton-shaped suture attachment structure, wherein the expanded areas ofthe button-shaped suture attachment structure serves to distribute theforce over a wider area.

FIG. 19 depicts a cross-sectional view of distal anchor 1900 comprisingdistal-most foldable member 1902, first inner foldable member 1904,second inner foldable member 1906, and proximal-most foldable member1908 in the deployed configuration. Distal anchor 1900 includesadditional distal protrusions on the foldable members for furtherrestraining the relative movement of the foldable members. Proximal-mostfoldable member 1908 comprises a first inner region 1910, a first distalprotrusion 1912, a second inner region 1914, and an outer region 1916.Outer region 1916 may comprise similar features and structures to outerregion 1814 described above with respect to distal anchor 1800.Similarly, the first inner region 1910 may comprises similar features toinner region 1810 described above with respect to distal anchor 1800.First distal protrusion 1912 may limit relative movement of second innerfoldable member 1906 relative to proximal-most foldable member 1908.

First distal protrusion 1912 of proximal-most foldable member 1908restrains the second inner foldable member 1906 in the width dimension.Protrusion 1914 may be characterized by angular region 1918, angularregion 1920, angular region 1922, and the length of the sides 1924 and1926 joining angular region 1918 to angular region 1920 and angularregion 1920 to angular region 1922, respectively. Angular region 1918may be characterized as the angle between the second inner region 1914and the side 1924. In some variations, this angle may be any anglebetween 180 and 270 degrees, including 180°, 190°, 200°, 210°, 220°,230°, 240°, 250°, 260°, and 270°, or any range between any two of theabove angles. In some further variations, angular region 1918 mayinclude an angle greater than 270 degrees to provide a “snap-fit” withan opposing surface of an adjacent foldable member. Angular region 1920may be characterized as the angle between the side 1924 and the side1926. In some variations, this angle may be any angle between 0 and 180degrees, including 0°, 10°, 20°, 30°, 40°, 50°, 60°, 70°, 80°, 90°,100°, 110°, 120°, 130°, 140°, 150°, 160°, 170°, and 180°, or any rangebetween any two of the above angles. Angular region 1922 may becharacterized as the angle between the first inner region 1910 and theside 1926. In some variations, this angle may be any angle between 180and 270 degrees, including 180°, 190°, 200°, 210°, 220°, 230°, 240°,250°, 260°, and 270°, or any range between any two of the above angles.In some further variations, angular region 1922 may include an anglegreater than 270 degrees to provide a “snap-fit” with an opposingsurface of an adjacent foldable member. Although angles 1918, 1920, and1922 are depicted in FIG. 19 as sharp corners, other variations mayinclude filleted or rounded angles. Sides 1924 and 1926 may be linear ornon-linear. For example, side 1924 may be curved where side 1926 may beflat. In other variations, side 1924 may be flat and side 1926 may becurved. In yet other variations, sides 1924 and 1926 may be both curvedor both flat. The length of each of sides 1924 and 1926 may becharacterized as a percentage of the width of the proximal-most foldablemember 1908 and may sometimes be about 5%, 10%, 20%, 30%, 40%, 45%, 50%,60%, 70%, 80%, 90%, or 95%, or any percentage range between any two ofthe above percentages.

The relative widths of first inner region 1910, first distal protrusion1912, second inner region 1914, and outer region 1916 may be varied. Insome variations, the widths of first inner region 1910, first distalprotrusion 1912, and second inner region 1914 may be characterized aspercentages of the width of outer region 1916 and may sometimes be about5%, 10%, 20%, 30%, 40%, 45%, 50%, 60%, 70%, 80%, 90%, or 95%, or anypercentage range between any two of the above percentages. In somevariations, the widths of first inner region 1910, first distalprotrusion 1912, and outer region 1916 may be characterized aspercentages of the width of second inner region 1914 and may sometimesbe about 5%, 10%, 20%, 30%, 40%, 45%, 50%, 60%, 70%, 80%, 90%, or 95%,or any percentage range between any two of the above percentages. Insome variations, the widths of first inner region 1910, second innerregion 1914, and outer region 1916 may be characterized as percentagesof the width of first distal protrusion 1912 and may sometimes be about5%, 10%, 20%, 30%, 40%, 45%, 50%, 60%, 70%, 80%, 90%, or 95%, or anypercentage range between any two of the above percentages. In somevariations, the widths of first distal protrusion 1912, second innerregion 1914, and outer region 1916 may be characterized as percentagesof the width of first inner region 1910 and may sometimes be about 5%,10%, 20%, 30%, 40%, 45%, 50%, 60%, 70%, 80%, 90%, or 95%, or anypercentage range between any two of the above percentages.

Second inner foldable member 1906 may comprise a recess 1928 on itsproximal surface corresponding to the first distal protrusion 1912 ofproximal-most foldable member 1908. Recess 1928 may be defined by thelength of the side surfaces and the angles created where the sides meeteach other and where the sides meet the proximal surface of second innerfoldable member. The lengths of the side surfaces may be characterizedas a percentage of the diameter of the proximal-most foldable member1908 and may sometimes be about 5%, 10%, 20%, 30%, 40%, 45%, 50%, 60%,70%, 80%, 90%, or 95%, or any percentage range between any two of theabove percentages. The angle may correspond to the angles of the distalprotrusion 1912 on proximal-most foldable member 1908.

First inner foldable member 1904 may comprise a recess on its proximalsurface corresponding to a distal protrusion on second foldable member1906. The recess may be defined by the length of the side surfaces andthe angles created where the sides meet each other and where the sidesmeet the proximal surface of second inner foldable member. The lengthsof the side surfaces may be characterized as a percentage of the widthof the proximal-most foldable member 1908 and may sometimes be about 5%,10%, 20%, 30%, 40%, 45%, 50%, 60%, 70%, 80%, 90%, or 95%, or anypercentage range between any two of the above percentages. The angle maycorrespond to the angles of the distal protrusion on second innerfoldable member 1906.

Distal-most foldable member 1902 may share similar geometries andfunctions as distal-most foldable member 1802.

Although FIGS. 18 and 19 illustrate one and two distal protrusions,respectively, on a distal surface of the proximal-most foldable member,other variations may have 3, 4, 5, or any number of protrusions.Further, although FIGS. 18 and 19 illustrate a distal protrusion on theperimeters of the proximal-most foldable member, first inner foldablemember, and second inner foldable member, other variations may have adistal recess on the perimeter of any of the foldable members.

FIGS. 20A to 20C depict various protrusions and recesses configured forcoupling adjacent foldable members. FIG. 20A depicts a cross-sectionalview of protrusion 2002 of a proximal foldable member configured to becoupled to a recess 2010 of a distal foldable member adjacent to theproximal foldable member. As can be seen in FIG. 20A, protrusion 2002comprises two angled sides 2004 and 2006 connected by a rounded apex2008. Recess 2010 comprises an inner proximal surface 2012 and an outerproximal surface 2014 connected by a fillet 2016. The distal foldablemember further comprises a distal surface including inner distal surface2018 and outer distal surface 2020. Inner distal surface 2020 may beoriented approximately in parallel to a distal surface of the proximalfoldable member. In this way, the distal foldable member provides morematerial behind the face at which the recess 2010 and protrusion 2002are forced together. That is, as the distal foldable member isrestrained, the inner proximal surface 2012 of the distal foldablemember is forced against the side 2004 of the proximal foldable member.Including additional material behind this point may provide additionalsupport to the distal foldable member when the two foldable members areforced together. By contrast, there is less force exerted on the outerproximal surface 2014. Accordingly, outer distal surface 2020 may begenerally parallel to the side 2006, resulting in a thinner outer regionof the distal foldable member. This may facilitate folding the foldablemember prior to insertion or may provide a reduction in manufacturingcosts.

FIG. 20B depicts a cross-sectional view of protrusion 2030 of a proximalfoldable member configured to be coupled to a recess 2032 of a thininner foldable member adjacent to the proximal foldable member, wherethe recess 2032 is further configured to be coupled to a recess 2034 ofa distal foldable member. Introducing a thin inner foldable memberbetween the distal and proximal foldable member may further distributethe pressure on the foldable members when in the restrainedconfiguration. In addition, inner foldable member may comprise anadhesive to strengthen the coupling between the proximal and distalfoldable members.

FIG. 20C depicts a cross-sectional view of protrusion 2040 of a proximalfoldable member configured to be coupled to a recess 2042 of a distalfoldable member. Recess 2042 includes a cavity 2044 which may facilitatecoupling of the distal and proximal foldable members without deformingthe proximal-most foldable member. More specifically, as the distalfoldable member is restrained, the recess 2042 slides laterally on theprotrusion 2040 so that the cavity 2044 moves to the other side ofprotrusion 2040. In this way, no additional forces may be exerted on theprotrusion 2040 in the lateral direction due to restraining the distalfoldable member.

FIG. 21 depicts a cross-sectional view of a portion 2100 of a distalanchor, comprising proximal-most foldable member 2102 and first innerfoldable member 2104. Proximal-most foldable member 2102 has distalprotrusion 2106 in its outer region. Distal protrusion 2106 may comprisethe geometry of any of the protrusions described herein. Inner region2108 of proximal-most foldable member 2102 comprises teeth 2110configured to restrain relative movement of the first inner foldablemember. The proximal surface of the first inner foldable member may alsocomprise teeth 2112 configured to engage with the teeth 2108 of theproximal-most foldable member. The distal surface of the first innerfoldable member 2104 may also comprise teeth 2114 configured to engagewith a proximal surface of an adjacent foldable member (not shown).

In some variations, teeth configured to restrain movement may take theform of a series of peaks and troughs. In some variations, the peaks andtroughs may be symmetrical. In other variations, the peaks and troughsmay not be symmetrical. In some variations, the peaks and troughs mayrepeat at constant distances. In other variations, the peaks and troughsmay be distributed unevenly throughout the surface of the foldablemember. In some variations, the peaks and troughs are rounded. Inothers, some or all of the peaks and troughs have pointed edges. In somevariations, an opposing surface of an adjacent foldable member may havea recess configured to receive the teeth. In other variations, theopposing surface of the adjacent foldable member does not include arecess for one or more of the teeth. In some variations, each surface ofa foldable member that opposes a surface of an adjacent foldable memberhas teeth. In other variations, one or more of the foldable members of adistal anchor does not include teeth. In some variations, the teethprotrude the same distance from the surface of the foldable member. Inother variations, one or more teeth protrude at a different distancefrom the surface of the foldable member. In some variations, thedistance the teeth protrude from the surface of the foldable member maybe characterized as a percentage of the thickness of the foldable memberwithout the teeth and may sometimes be about 5%, 10%, 20%, 30%, 40%,45%, 50%, 60%, 70%, 80%, 90%, or 95%, or any percentage range betweenany two of the above percentages. In some variations, the thickness ofthe foldable member without the teeth may be characterized as apercentage of the distance the teeth protrude from the surface of thefoldable member and may sometimes be about 5%, 10%, 20%, 30%, 40%, 45%,50%, 60%, 70%, 80%, 90%, or 95%, or any percentage range between any twoof the above percentages.

FIG. 22 depicts a cross-sectional view of a portion 2200 of a distalanchor comprising teeth between adjacent foldable members 2202 and 2204.Proximal-most foldable member 2202 may have some features which aresimilar to proximal-most foldable member 2102 described above withrespect to FIG. 21. Proximal-most foldable member 2202 may be thickerthan proximal-most foldable member 2102, resulting in a wider outerregion 2206. First inner foldable member 2204 may have some featureswhich are similar to first inner foldable member 2104 described abovewith respect to FIG. 21. Proximal-most foldable member 2202 and firstinner foldable member 2204 may comprise central regions 2208 and 2210,respectively, without teeth. An aperture may be positioned in centralregions 2208 and 2210 for receiving a suture.

FIG. 23A depicts a cross-sectional view of a set 2300 of teethconfigured for coupling adjacent foldable members. Each tooth maycomprise a first angular region 2304, a first side 2306, a secondangular region 2308, a second side 2310, a third angular region 2312, athird side 2314, and a fourth angular region 2316. First angular region2304 may be characterized by the angle created by the surface of thefoldable member 2302 and the first side 2306, where the angle maysometimes be 180°, 190°, 200°, 210°, 220°, 230°, 240°, 250°, 260°, and270°, or any range between any two of the above angles. First side 2306may be characterized as a percentage of the thickness of the foldablemember and may sometimes be 5%, 10%, 20%, 30%, 40%, 45%, 50%, 60%, 70%,80%, 90%, or 95%, or any percentage range between any two of the abovepercentages. Second angular region 2308 may be characterized by theangle created by the first side 2306 and the second side 2310, where theangle may sometimes be 180°, 190°, 200°, 210°, 220°, 230°, 240°, 250°,260°, and 270°, or any range between any two of the above angles. Secondside 2310 may be characterized as a percentage of the thickness of thefoldable member and may sometimes be 5%, 10%, 20%, 30%, 40%, 45%, 50%,60%, 70%, 80%, 90%, or 95%, or any percentage range between any two ofthe above percentages. Third angular region 2312 may be characterized bythe angle created by the second side 2310 and the third side 2314, wherethe angle may sometimes be 270°, 280°, 290°, 300°, 310°, 320°, 330°,340°, 350°, and 360°. Third side 2314 may be characterized as apercentage of the thickness of the foldable member and may sometimes be5%, 10%, 20%, 30%, 40%, 45%, 50%, 60%, 70%, 80%, 90%, or 95%, or anypercentage range between any two of the above percentages. Fourthangular region 2304 may be characterized by the angle created by thesurface of the foldable member 2302 and the third side 2314, where theangle may sometimes be 270°, 280°, 290°, 300°, 310°, 320°, 330°, 340°,350°, and 360°, or any range between any two of the above angles.

FIG. 23B depicts a cross-sectional view of a set 2330 of teethconfigured for coupling adjacent foldable members. Each tooth maycomprise a first angular region 2334, a first side 2336, a secondangular region 2338, a second side 2340, and a third angular region2332. First angular region 2334 may be characterized by the anglecreated by the surface of the foldable member 2332 and the first side2336, where the angle may sometimes be 180°, 190°, 200°, 210°, 220°,230°, 240°, 250°, 260°, and 270°, or any range between any two of theabove angles. First side 2336 may be curved, wherein the length of thecurve is characterized as a percentage of the thickness of the foldablemember and may sometimes be 5%, 10%, 20%, 30%, 40%, 45%, 50%, 60%, 70%,80%, 90%, or 95%, or any percentage range between any two of the abovepercentages. Second angular region 2338 may be characterized by theangle created by the first side 2336 and the second side 2340, where theangle may sometimes be 180°, 190°, 200°, 210°, 220°, 230°, 240°, 250°,260°, 270°, 280°, 290°, 300°, 310°, 320°, 330°, 340°, 350°, and 360°, orany range between any two of the above angles. Second side 2340 may becharacterized as a percentage of the thickness of the foldable memberand may sometimes be 5%, 10%, 20%, 30%, 40%, 45%, 50%, 60%, 70%, 80%,90%, or 95%, or any percentage range between any two of the abovepercentages Third angular region 2342 may be characterized by the anglecreated by the surface of the foldable member 2332 and the third side2340, where the angle may sometimes be 270°, 280°, 290°, 300°, 310°,320°, 330°, 340°, 350°, and 360°, or any range between any two of theabove angles.

FIG. 23C shows a cross-sectional view of pair 2350 of foldable members,first foldable member 2352 and second foldable member 2354. Firstfoldable member 2352 may comprise recesses 2362 configured to receiveteeth 2360 on second foldable member 2354. As can be seen in FIG. 23C,the teeth and recesses are symmetrical about a center point of eachfoldable member. This may facilitate an annular rib on the foldablemember when viewed in three-dimensions, that is, when the cross-sectiondepicted in FIG. 23C is revolved 180 degrees. In other variations, theteeth may not be symmetrical about a center point of each foldablemember.

FIG. 24 depicts a cross-sectional view of foldable member 2400 whichcomprises teeth 2402 and 2404. Teeth 2402 and 2404 may include a surfaceof relatively large curvature, thereby facilitating a snap-fit whenfoldable member 2400 engages recesses in an adjacent foldable member.Teeth 2402 and 2404 may be configured to move transversely within therecess of the adjacent foldable member as the pair of foldable membersare forced together.

FIG. 25 illustrates a cut-away, exploded view of a distal anchor 2500comprising a distal-most foldable member 2502, an inner foldable member2504, and a proximal-most foldable member 2506. Inner foldable member2504 and proximal-most foldable member 2506 comprise recesses 2522 and2532, respectively, configured to receive the distally adjacent foldablemember. The design of distal anchor 2500 may serve to relativelyrestrain the foldable members while sill reducing manufacturing costs.Proximal-most foldable member 2530 may further comprise structure on itsproximal surface to enable the distal anchor 2500 to better couple to asurface of a body lumen at the distal opening of a fistula tract.

Distal-most foldable member 2502 comprises generally concave distal andproximal surfaces. As illustrated in FIG. 25, the distal surface ofdistal-most foldable member 2502 has a greater curvature than theproximal surface, that is, the distal surface of distal-most foldablemember 2502 has a smaller radius of curvature than the proximal surface.The greater curvature of the distal surface results in a thicker centralregion, which may provide additional structural support when a suture(not shown) is attached to a suture attachment structure (not shown) onthe distal-most foldable member 2502. In some variations, the radius ofcurvature of the distal surface may be characterized as a percentage ofthe radius of curvature of the proximal surface and sometimes may be75%, 80%, 85%, 90%, 95%, 100%, or any percentage range between any twoof the above percentages. In other variations, the proximal surface ofthe distal-most foldable member 2502 comprises a greater curvature thanthe distal surface that is, the proximal surface of distal-most foldablemember 2502 has a smaller radius of curvature than the distal surface.In some variations, the radius of curvature of the proximal surface maybe characterized as a percentage of the radius of curvature of thedistal surface and sometimes may be 75%, 80%, 85%, 90%, 95%, 100%, orany percentage range between any two of the above percentages.Distal-most foldable member 2502 also comprises a distal angular region2508, a perimeter surface 2510, and a proximal angular region 2512.Distal angular region 2508, perimeter surface 2510, and proximal angularregion 2512 may be configured to mate distal-most foldable member 2502with a recess in inner foldable member 2504. Distal angular region 2508may be an arc with a radius and an angle. In some variations, the radiusis characterized as a percentage of the diameter of the distal-mostfoldable member, and may sometimes be 5%, 10%, 20%, 30%, 40%, 45%, 50%,60%, 70%, 80%, 90%, or 95%, or any percentage range between any two ofthe above percentages. In some variations, the angle may sometimes be0°, 10°, 20°, 30°, 40°, 50°, 60°, 70°, 80°, 90°, 100°, 110°, 120°, 130°,140°, 150°, 160°, 170°, and 180°, or any range between any two of theabove angles. In other variations, distal angular region 2508 may be apointed corner created by the distal surface of distal-most foldablemember 2502 and the perimeter surface 2510. In some variations, theangle of the pointed corner may be 90°, 100°, 110°, 120°, 130°, 140°,150°, 160°, 170°, and 180°, or any range between any two of the aboveangles. In some variations, perimeter surface 2510 may comprise a lengthcharacterized as a percentage of the diameter of the distal-mostfoldable member, and may sometimes be 1%, 2%, 3%, 4%, 5%, 10%, 15%, 20%,25%, 30%, or any percentage range between any two of the abovepercentages. In some variations, proximal angular region 2512 may be apointed corner created by the proximal surface of distal-most foldablemember 2502 and the perimeter surface 2510. In some variations, theangle of the pointed corner may be 0°, 30°, 60°, 90°, 120°, 150°, 180°,or any range between any two of the above angles.

Inner foldable member 2504 comprises a proximal surface and a distalsurface. As with distal-most foldable member 2502, the proximal surfacemay have a different curvature than the distal surface. The distalsurface comprises an elevated region 2520 and a recessed region 2522.Elevated region 2520 may include a distal angular region 2514, aperimeter surface 2516, and a proximal angular region 2518. Distalangular region 2514, perimeter surface 2516, and proximal angular region2518 may comprise any of the geometries discussed above with respect todistal angular region 2508, perimeter surface 2510, and proximal angularregion 2512. Recessed region 2522 may be configured to mate innerfoldable member 2504 with the proximal surface of distal-most foldablemember 2502. Recessed region 2522 may comprise a distal angular region2524, an interior surface 2526, and a proximal angular region 2528.Distal angular region 2524, interior surface 2526, and proximal angularregion 2528 may be configured to mate recess 2522 of inner foldablemember 2504 with distal-most foldable member 2502. Distal angular region2524 may be an arc with a radius and an angle. In some variations, theradius is characterized as a percentage of the diameter of the innerfoldable member, and may sometimes be 5%, 10%, 20%, 30%, 40%, 45%, 50%,60%, 70%, 80%, 90%, or 95%, or any percentage range between any two ofthe above percentages. In some variations, the angle may sometimes be0°, 10°, 20°, 30°, 40°, 50°, 60°, 70°, 80°, 90°, 100°, 110°, 120°, 130°,140°, 150°, 160°, 170°, and 180°, or any range between any two of theabove angles. In other variations, distal angular region 2524 may be apointed corner created by the surface of elevation 2520 and the interiorsurface 2526. In some variations, the angle of the pointed corner may be90°, 100°, 110°, 120°, 130°, 140°, 150°, 160°, 170°, and 180°, or anyrange between any two of the above angles. In some variations, interiorsurface 2526 may comprise a length characterized as a percentage of thediameter of the inner foldable member, and may sometimes be 1%, 2%, 3%,4%, 5%, 10%, 15%, 20%, 25%, 30%, or any percentage range between any twoof the above percentages. In some variations, proximal angular region2528 may be a pointed corner created by the surface of recess 2522 andthe interior surface 2526. In some variations, the angle of the pointedcorner may be 0°, 10°, 20°, 30°, 60°, 90°, 120°, 150°, 180°, or anyrange between any two of the above angles.

Proximal-most foldable member 2506 comprises a proximal surface and adistal surface. The distal surface comprises a sloped region 2530 and arecessed region 2532. Recessed region 2532 may be configured to mateinner foldable member 2504 with the distal surface of proximal-mostfoldable member 2506. Recessed region 2532 may comprise a distal angularregion 2534, an interior surface 2536, and a proximal angular region2538. Distal angular region 2534 may be an arc with a radius and anangle. In some variations, the radius is characterized as a percentageof the diameter of the proximal-most foldable member, and may sometimesbe 55%, 10%, 20%, 30%, 40%, 45%, 50%, 60%, 70%, 80%, 90%, or 95%, or anypercentage range between any two of the above percentages. In somevariations, the angle may sometimes be 0°, 10°, 20°, 30°, 40°, 50°, 60°,70°, 80°, 90°, 100°, 110°, 120°, 130°, 140°, 150°, 160°, 170°, and 180°,or any range between any two of the above angles. In other variations,distal angular region 2534 may be a pointed corner created by thesurface of sloped region 2530 and the interior surface 2536. In somevariations, the angle of the pointed corner may be 90°, 100°, 110°,120°, 130°, 140°, 150°, 160°, 170°, and 180°, or any range between anytwo of the above angles. In some variations, interior surface 2536 maycomprise a length characterized as a percentage of the diameter of theinner foldable member, and may sometimes be 1%, 2%, 3%, 4%, 5%, 10%,15%, 20%, 25%, 30%, or any percentage range between any two of the abovepercentages. In some variations, proximal angular region 2538 may be apointed corner created by the surface of recess 2532 and the interiorsurface 2536. In some variations, the angle of the pointed corner may be0°, 10°, 20°, 30°, 40°, 50°, 60°, 70°, 80°, 90°, 100°, 110°, 120°, 130°,140°, 150°, 160°, 170°, and 180°, or any range between any two of theabove angles.

The proximal surface of proximal-most foldable member 2506 may beconfigured to provide additional support. The proximal surface ofproximal-most foldable member may include a recess 2544 and a proximalprotrusion 2546. Both recess 2544 and proximal protrusion 2546 may bedefined by an arc of a length and an angle. In some variations, thelength of the arc is characterized as a percentage of the diameter ofthe inner foldable member, and may sometimes be 1%, 2%, 3%, 4%, 5%, 10%,20%, 30%, 40%, 45%, 50%, 60%, 70%, 80%, 90%, or 95%, or any percentagerange between any two of the above percentages. In some variations, theangle may sometimes be 0°, 10°, 20°, 30°, 40°, 50°, 60°, 70°, 80°, 90°,100°, 110°, 120°, 130°, 140°, 150°, 160°, 170°, and 180°, or any rangebetween any two of the above angles. Proximal protrusion 2546 maycomprise an inner sealing region to prevent ingress of fistula materialto the body lumen. Angular region 2542 may comprise an outer edge regionof the proximal-most foldable member. In some variations, the outer edgeregion is oriented at an acute angle to the inner sealing region. Insome embodiments, the position of the proximal protrusion may becharacterized as a percentage of the diameter of the proximal-mostfoldable member and may sometimes be 5%, 10%, 20%, 30%, 40%, 45%, 50%,60%, 70%, 80%, 90%, or 95%, or any percentage range between any two ofthe above percentages.

Although distal anchor 2500 is illustrated with three foldable members,other variations may include four or more foldable members. Additionalfoldable members may comprise additional inner foldable membersconfigured to mate to adjacent foldable members. In addition, althoughthe foldable members are illustrated as having an overall curved form,in some variations the foldable members may have an overall planar form.Moreover, any of the overall shapes described herein may be employed.The distal-most and inner foldable members are depicted with a smoothproximal surface, but some variations may include topographical featuresconfigured to further restrain relative movement between the foldablemembers, such as those described herein. In addition, although a suture,a suture attachment structure, and apertures for threading a suture arenot illustrated in FIG. 25, some variations include all or some of asuture, a suture attachment structure, and apertures for threading asuture, such as those described herein.

FIG. 26 illustrates a cut-away, exploded view of a distal anchor 2600comprising distal-most foldable member 2602, first inner foldable member2604, second inner foldable member 2606, and proximal-most foldablemember 2608. Foldable members 2602, 2604, and 2606, and 2610 arerelatively less curved than the foldable members of distal anchor 2500.Second inner foldable member 2606 and proximal-most foldable member 2608comprise annular ribs 2620 and 2630, respectively. Annular ribs 2620 and2630 may serve to relatively restrain the foldable members of distalanchor 2600 is in the deployed configuration. The distal surface of eachof first inner foldable member 2604, second inner foldable member 2606,and proximal-most foldable member 2608 may comprise an outer distallyprotruding region and an inner recess. As can be seen in FIG. 26, thewidth of the outer regions may vary. In other variations, the widths ofthe outer regions are the same.

As depicted in FIG. 26, annular rib 2620 may be aligned with annular rib2630, and annular rib 2630 may be aligned with a side surface of arecess in first inner foldable member 2604. In some variations, theannular ribs are not aligned with features on the distal face of theadjacent foldable member. The positioning of the annular ribs on eachfoldable member may be characterized by a diameter that is a percentageof the overall diameter of the distal anchor 2600, and may sometimes be5%, 10%, 20%, 30%, 40%, 45%, 50%, 60%, 70%, 80%, 90%, or 95%, or anypercentage range between any two of the above percentages. The annularribs may also comprise a width from the bottom of the slope of one faceto the bottom of the slope of the other face, that is, a width of thebase of the rib. The widths of the annular ribs may be characterized asa percentage of the overall diameter of the distal anchor 2600, and maysometimes be 1%, 2%, 3%, 4%, 5%, 10%, 15%, 20%, 25%, 30%, or anypercentage range between any two of the above percentages. Althoughannular rib 2630 is illustrated as comprising a pointed apex, othervariations may include a rounded or flat apex, such as any of theprotrusion geometries discussed herein. Similarly, annular rib 2620 isillustrated as comprising a flat apex, but other variations may includea rounded or pointed apex, such as any of the protrusion geometriesdiscussed herein.

Distal-most foldable member 2602 comprises a generally planar proximalsurface and a curved distal surface, with a side surface connecting theproximal and distal surfaces. The side surface of distal-most foldablemember 2602 may be oriented at an acute angle to the height dimension,wherein the angle may sometimes be 90°, 100°, 110°, 120°, 130°, 140°,150°, 160°, 170°, and 180°, or any range between any two of the aboveangles. The thickness of distal-most foldable member 2602 may becharacterized as a percentage of the overall thickness of the distalanchor 2600 in the deployed configuration, and may sometimes be 5%, 10%,20%, 30%, 40%, 45%, 50%, 60%, 70%, 80%, 90%, or 95%, or any percentagerange between any two of the above percentages. The diameter ofdistal-most foldable member 2602 may be characterized as a percentage ofthe diameter of proximal-most foldable member 2608, and may sometimes be5%, 10%, 20%, 30%, 40%, 45%, 50%, 60%, 70%, 80%, 90%, or 95%, or anypercentage range between any two of the above percentages.

First inner foldable member 2604 may comprise a protruding outer regionand a recess on its distal face. First inner foldable member 2604 mayalso comprise a recess on its proximal face, which may be aligned withan annular rib on second inner foldable member 2606. The protrusions andrecess of first inner foldable member 2604 may comprise any of theprotrusion and recess geometries described herein.

Second inner foldable member 2606 may comprise a protruding outerregion, a first recess, an annular rib, and a second recess on itsdistal face. The relative size and positions of the first and secondrecesses may be determined by the positioning and size of the annularrib. Second inner foldable member 2606 may comprise a recess on itsproximal face. The protrusions and recess of second inner foldablemember 2606 may comprise any of the protrusion and recess geometriesdescribed herein.

Proximal-most foldable member 2608 may comprise a protruding outerregion, a first recess, an annular rib, and a second recess on itsdistal face. The relative size and positions of the first and secondrecesses may be determined by the positioning and size of the annularrib. Proximal-most foldable member 2608 may comprise a smooth proximalface. The protrusions and recess of proximal-most foldable member 2608may comprise any of the protrusion and recess geometries describedherein.

FIG. 27 depicts a cut-away, exploded view of a distal anchor 2700comprising distal-most foldable member 2702, first inner foldable member2704, second inner foldable member 2706, and proximal-most foldablemember 2708. Foldable members 2702-2708 may have less curvature than thefoldable members described above with respect to distal anchor 2500. Inaddition, inner foldable members 2704 and 2706 may have recessesconfigured to receive a proximal surface of the distally adjacentfoldable member and protruding outer regions configured to relativelyrestrain the distally adjacent foldable members, similar to the innerfoldable members in distal anchors 2500 and 2600. The recesses andprotruding outer regions of inner foldable members 2704 and 2706 maytake any of the geometries described above with respect to distalanchors 2704 and 2706.

Proximal-most foldable member comprises annular ribs 2710, 2712, 2714,2718, and 2720. Annular ribs 2710, 2712, 2714, 2718, and 2720 mayprovide a separation between the proximal-most foldable member 2708 andthe second inner foldable member 2706 while also providing a resistanceto relative motion between the two adjacent foldable members. Althoughsix annular ribs are shown in FIG. 27, other variations may includeother numbers of annular ribs, including 2, 3, 4, 5, 7, 8, 9 and 10annular ribs. Further, although the annular ribs in FIG. 27 areconcentric, in other variations the annular ribs are not concentric.Further, the annular ribs in FIG. 27 are separated by an equal distance,but in other variations, the annular ribs may be separated by differentdistances. The geometry of each annular rib may be characterized by aninner surface that is oriented approximately in parallel to the heightdimension and an outer surface that is oriented at an angle to theheight dimension, wherein the angle may sometimes be 0°, 10°, 20°, 30°,40°, 50°, 60°, 70°, 80°, and 90°, or any range between any two of theabove angles. In some variations, the height of the inner surface ofeach rib may be characterized as a percentage of the thickness of theproximal-most member without the ribs and may sometimes be 5%, 10%, 20%,30%, 40%, 45%, 50%, 60%, 70%, 80%, 90%, or 95%, or any percentage rangebetween any two of the above percentages. In other variations, thethickness of the proximal-most member without the ribs may becharacterized as a percentage of the height of the inner surface of eachrib and may sometimes be 5%, 10%, 20%, 30%, 40%, 45%, 50%, 60%, 70%,80%, 90%, or 95%, or any percentage range between any two of the abovepercentages.

FIG. 28 depicts a cross-sectional exploded view of a distal anchor 2800comprising distal-most foldable member 2802, inner foldable member 2804,and proximal-most foldable member 2806. Foldable members 2802, 2804, and2806 may have greater curvature than the foldable members of distalanchors 2500, 2600, and 2700. In addition, a proximal protrusion oninner foldable member 2804 and proximal-most foldable member 2806 mayprotrude further than the proximal protrusions of distal anchors 2500,2600, and 2700. Inner foldable member 2804 also include a recess at thebase of the proximal protrusion to improve mating to the distallyadjacent foldable member. Further, the distal surface of distal-mostfoldable member 2802 may be tapered at its perimeter to improve matingwith proximal-most foldable member 2802.

Distal-most foldable member 2802 includes an outer region on its distalsurface which may be tapered to improve mating. The outer regionincludes a distal angular region 2808, a planar surface 2810, and aproximal angular region 2812. Distal angular region 2808 may create anobtuse angle where the distal surface of distal-most foldable member2802 and planar surface 2810 meet. In some variations, the angle maysometimes be 90°, 100°, 110°, 120°, 130°, 140°, 150°, 160°, 170°, and180°, or any range between any two of the above angles. Proximal angularregion 2812 may be an arc with a radius and an angle. In somevariations, the radius is characterized as a percentage of the thicknessof the distal-most foldable member, and may sometimes be 5%, 10%, 20%,30%, 40%, 45%, 50%, 60%, 70%, 80%, 90%, or 95%, or any percentage rangebetween any two of the above percentages. In some variations, thethickness of the distal-most foldable member is characterized as apercentage of the radius of proximal angular region 2812, and maysometimes be 5%, 10%, 20%, 30%, 40%, 45%, 50%, 60%, 70%, 80%, 90%, or95%, or any percentage range between any two of the above percentages.In some variations, the angle of proximal angular region 2812 may be 0°,10°, 20°, 30°, 40°, 50°, 60°, 70°, 80°, 90°, 100°, 110°, 120°, 130°,140°, 150°, 160°, 170°, 180°, or any range between any two of the aboveangles. In some variations, the length of planar surface 2810 ischaracterized as a percentage of the thickness of the distal-mostfoldable member, and may sometimes be 5%, 10%, 20%, 30%, 40%, 45%, 50%,60%, 70%, 80%, 90%, or 95%, or any percentage range between any two ofthe above percentages. In some variations, the thickness of thedistal-most foldable member is characterized as a percentage of thelength of planar surface 2810, and may sometimes be 5%, 10%, 20%, 30%,40%, 45%, 50%, 60%, 70%, 80%, 90%, or 95%, or any percentage rangebetween any two of the above percentages.

Inner foldable member 2804 includes an outer region on its distalsurface which comprises a protrusion and a recess. The recess comprisesa distal angular region 2814, a first planar surface 2816, a proximalangular region 2824, and a second planar surface 2820. Distal angularregion 2814 may create an obtuse angle where the distal surface of innerfoldable member 2804 and first planar surface 2816 meet. In somevariations, the angle may sometimes be 90°, 100°, 110°, 120°, 130°,140°, 150°, 160°, 170°, and 180°. In some variations, the length offirst planar surface 2816 is characterized as a percentage of thethickness of the inner foldable member, and may sometimes be 5%, 10%,20%, 30%, 40%, 45%, 50%, 60%, 70%, 80%, 90%, or 95%, or any percentagerange between any two of the above percentages. In some variations, thethickness of the inner foldable member is characterized as a percentageof the length of first planar surface 2816, and may sometimes be 5%,10%, 20%, 30%, 40%, 45%, 50%, 60%, 70%, 80%, 90%, or 95%, or anypercentage range between any two of the above percentages. Proximalangular region 2824 may be an arc with a radius and an angle. In somevariations, the radius is characterized as a percentage of the thicknessof the inner foldable member, and may sometimes be 5%, 10%, 20%, 30%,40%, 45%, 50%, 60%, 70%, 80%, 90%, or 95%, or any percentage rangebetween any two of the above percentages. In some variations, thethickness of the inner foldable member is characterized as a percentageof the radius of proximal angular region 2824, and may sometimes be 5%,10%, 20%, 30%, 40%, 45%, 50%, 60%, 70%, 80%, 90%, or 95%, or anypercentage range between any two of the above percentages. In somevariations, the angle of proximal angular region 2824 may be 0°, 10°,20°, 30°, 40°, 50°, 60°, 70°, 80°, 90°, 100°, 110°, 120°, 130°, 140°,150°, 160°, 170°, and 180°, or any range between any two of the aboveangles. In some variations, the length of second planar surface 2820 ischaracterized as a percentage of the thickness of the inner foldablemember, and may sometimes be 5%, 10%, 20%, 30%, 40%, 45%, 50%, 60%, 70%,80%, 90%, or 95%, or any percentage range between any two of the abovepercentages. In some variations, the thickness of the inner foldablemember is characterized as a percentage of the length of second planarsurface 2820, and may sometimes be 5%, 10%, 20%, 30%, 40%, 45%, 50%,60%, 70%, 80%, 90%, or 95%, or any percentage range between any two ofthe above percentages. The protrusion on the outer region of innerfoldable member 2804 comprises a distal angular region 2818, a planarsurface 2822, and a proximal angular region 2826. Distal angular region2818 may be an arc with a radius and an angle. In some variations, theradius is characterized as a percentage of the thickness of the innerfoldable member, and may sometimes be 5%, 10%, 20%, 30%, 40%, 45%, 50%,60%, 70%, 80%, 90%, or 95%, or any percentage range between any two ofthe above percentages. In some variations, the thickness of the innerfoldable member is characterized as a percentage of the radius of distalangular region 2818, and may sometimes be 5%, 10%, 20%, 30%, 40%, 45%,50%, 60%, 70%, 80%, 90%, or 95%, or any percentage range between any twoof the above percentages. In some variations, the angle of distalangular region 2818 may be 0°, 10°, 20°, 30°, 40°, 50°, 60°, 70°, 80°,90°, 100°, 110°, 120°, 130°, 140°, 150°, 160°, 170°, 180°, or any rangebetween any two of the above angles. In some variations, the length ofplanar surface 2822 is characterized as a percentage of the thickness ofthe inner foldable member, and may sometimes be 5%, 10%, 20%, 30%, 40%,45%, 50%, 60%, 70%, 80%, 90%, or 95%, or any percentage range betweenany two of the above percentages. In some variations, the thickness ofthe inner foldable member is characterized as a percentage of the lengthof planar surface 2822, and may sometimes be 5%, 10%, 20%, 30%, 40%,45%, 50%, 60%, 70%, 80%, 90%, or 95%, or any percentage range betweenany two of the above percentages. Proximal angular region 2820 may be anarc with a radius and an angle. In some variations, the radius ischaracterized as a percentage of the thickness of the inner foldablemember, and may sometimes be 5%, 10%, 20%, 30%, 40%, 45%, 50%, 60%, 70%,80%, 90%, or 95%, or any percentage range between any two of the abovepercentages. In some variations, the thickness of the inner foldablemember is characterized as a percentage of the radius of proximalangular region 2820, and may sometimes be 5%, 10%, 20%, 30%, 40%, 45%,50%, 60%, 70%, 80%, 90%, or 95%, or any percentage range between any twoof the above percentages. In some variations, the angle of proximalangular region 2820 may be 0°, 10°, 20°, 30°, 40°, 50°, 60°, 70°, 80°,90°, 100°, 110°, 120°, 130°, 140°, 150°, 160°, 170°, 180°, or any rangebetween any two of the above angles.

Proximal-most foldable member 2806 includes an outer region on itsdistal surface which comprises a protrusion and a recess. The recesscomprises a distal angular region 2830, a first planar surface 2832, aproximal angular region 2836, and a second planar surface 2834. Distalangular region 2830 may create an obtuse angle where the distal surfaceof proximal-most foldable member 2806 and first planar surface 2832meet. In some variations, the angle may sometimes be 90°, 100°, 110°,120°, 130°, 140°, 150°, 160°, 170°, 180°, or any range between any twoof the above angles. In some variations, the length of first planarsurface 2832 is characterized as a percentage of the thickness of theproximal-most foldable member, and may sometimes be 5%, 10%, 20%, 25%,30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, or 95%.In some variations, the thickness of the proximal-most foldable memberis characterized as a percentage of the length of first planar surface2832, and may sometimes be 5%, 10%, 20%, 25%, 30%, 35%, 40%, 45%, 50%,55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, or 95%. Proximal angular region2836 may be an arc with a radius and an angle. In some variations, theradius is characterized as a percentage of the thickness of theproximal-most foldable member, and may sometimes be 5%, 10%, 20%, 25%,30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, or 95%.In some variations, the thickness of the proximal-most foldable memberis characterized as a percentage of the radius of proximal angularregion 2836, and may sometimes be 5%, 10%, 20%, 30%, 40%, 45%, 50%, 60%,70%, 80%, 90%, or 95%, or any percentage range between any two of theabove percentages. In some variations, the angle of proximal angularregion 2836 may be 0°, 10°, 20°, 30°, 40°, 50°, 60°, 70°, 80°, 90°,100°, 110°, 120°, 130°, 140°, 150°, 160°, 170°, and 180°. In somevariations, the length of second planar surface 2834 is characterized asa percentage of the thickness of the proximal-most foldable member, andmay sometimes be 5%, 10%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%,65%, 70%, 75%, 80%, 85%, 90%, or 95%. In some variations, the thicknessof the proximal-most foldable member is characterized as a percentage ofthe length of second planar surface 2834, and may sometimes be 5%, 10%,20%, 30%, 40%, 45%, 50%, 60%, 70%, 80%, 90%, or 95%, or any percentagerange between any two of the above percentages. The protrusion on theouter region of proximal-most foldable member 2806 comprises a distalangular region 2842, a planar surface 2840, and a proximal angularregion 2838. Distal angular region 2842 may be an arc with a radius andan angle. In some variations, the radius is characterized as apercentage of the thickness of the proximal-most foldable member, andmay sometimes be 5%, 10%, 20%, 30%, 40%, 45%, 50%, 60%, 70%, 80%, 90%,or 95%, or any percentage range between any two of the abovepercentages. In some variations, the thickness of the proximal-mostfoldable member is characterized as a percentage of the radius of distalangular region 2842, and may sometimes be 5%, 10%, 20%, 30%, 40%, 45%,50%, 60%, 70%, 80%, 90%, or 95%, or any percentage range between any twoof the above percentages. In some variations, the angle of distalangular region 2842 may be 0°, 10°, 20°, 30°, 40°, 50°, 60°, 70°, 80°,90°, 100°, 110°, 120°, 130°, 140°, 150°, 160°, 170°, 180°, or any rangebetween any two of the above angles. In some variations, the length ofplanar surface 2840 is characterized as a percentage of the thickness ofthe proximal-most foldable member, and may sometimes be 5%, 10%, 20%,30%, 40%, 45%, 50%, 60%, 70%, 80%, 90%, or 95%, or any percentage rangebetween any two of the above percentages. In some variations, thethickness of the proximal-most foldable member is characterized as apercentage of the length of planar surface 2840, and may sometimes be5%, 10%, 20%, 30%, 40%, 45%, 50%, 60%, 70%, 80%, 90%, or 95%, or anypercentage range between any two of the above percentages. Proximalangular region 2838 may be an arc with a radius and an angle. In somevariations, the radius is characterized as a percentage of the thicknessof the proximal-most foldable member, and may sometimes be 5%, 10%, 20%,30%, 40%, 45%, 50%, 60%, 70%, 80%, 90%, or 95%, or any percentage rangebetween any two of the above percentages. In some variations, thethickness of the proximal-most foldable member is characterized as apercentage of the radius of proximal angular region 2838, and maysometimes be 5%, 10%, 20%, 30%, 40%, 45%, 50%, 60%, 70%, 80%, 90%, or95%, or any percentage range between any two of the above percentages.In some variations, the angle of proximal angular region 2838 may be 0°,10°, 20°, 30°, 40°, 50°, 60°, 70°, 80°, 90°, 100°, 110°, 120°, 130°,140°, 150°, 160°, 170°, 180°, or any range between any two of the aboveangles.

FIG. 29 depicts a cut-away, exploded view of a distal anchor 2900comprising distal-most foldable member 2902, first inner foldable member2904, second inner foldable member 2906, and proximal-most foldablemember 2908. Distal-most foldable member 2902, first inner foldablemember 2904, second inner foldable member 2906, and proximal-mostfoldable member 2908 may have less curvature than the foldable membersof distal anchor 2800. Distal-most foldable member 2902 may a taperedouter region similar to the tapered outer region of distal-most foldablemember 2802. First inner foldable member 2904, second inner foldablemember 2906, and proximal-most foldable member 2908 may have recessesand protrusions in outer regions similar to those described above withrespect to distal anchor 2800. The protrusion in the outer region ofproximal-most foldable member 2908 may be located inward from theperimeter of proximal-most foldable member 2908, leaving a relativelythin region 2930 at the outermost part of proximal-most foldable member2908. The position of the protrusion of the proximal-most foldablemember may be characterized as a percentage of the diameter ofproximal-most foldable member 2908, and sometimes may be 5%, 10%, 20%,30%, 40%, 45%, 50%, 60%, 70%, 80%, 90%, or 95%, or any percentage rangebetween any two of the above percentages. Proximal-most foldable member2908 may also include features on its proximal surface configured toengage the surface of a body lumen. These features may be similar ingeometry to curves 2544 and 2546 of distal anchor 2500. In addition,distal-most foldable member 2902, first inner foldable member 2904,second inner foldable member 2906, and proximal-most foldable member2908 may comprise annular ribs 2910, 2912, 2914, 2916, 2918, 2920, 2922,and 2924 on their proximal and/or distal surfaces. These annular ribsmay restrain relative movement of the foldable members when the foldablemembers are in the restrained configuration. Each annular rib has anassociated annular rib on the opposing surface of the adjacent foldablemember. As the foldable members are restrained by a suture (not shown),each pair of annular ribs are forced together, thereby limiting therelative movement between the adjacent foldable members. The opposingannular ribs may comprise parallel surfaces on their opposing faces.Annular ribs 2910, 2912, 2914, 2916, 2918, 2920, 2922, and 2924 maycomprise a similar geometry as the annular ribs described above withrespect to distal anchor 2700.

FIG. 30 depicts a cross-sectional view of a distal anchor 3000,comprising distal-most foldable member 3002, first inner foldable member3004, second inner foldable member 3006, and proximal-most foldablemember 3008. Distal-most foldable member 3002, first inner foldablemember 3004, and second inner foldable member 3006 may comprise similargeometries to distal-most foldable member 1802, first inner foldablemember 1804, and second inner foldable member 1806 discussed above withrespect to distal anchor 1800. In some variations, as depicted in FIG.30, the distal-most foldable member 3002, first inner foldable member3004, and second inner foldable member 3006 may be curved. Distal-mostfoldable member 3002, first inner foldable member 3004, and second innerfoldable member 3006 may have less curvature than the foldable membersof distal anchor 2900. The proximal surface of proximal-most foldablemember may be substantially planar. The distal surface of proximal-mostfoldable member 3008 may comprise an outer region with a protrusion 3012similar to protrusion 2546 discussed above with respect to distal anchor2500. Proximal-most foldable member 3008 may also comprise a flatsurface 3010 connecting the edge of the proximal-most foldable member toprotrusion 3012. The proximal surface of proximal-most member 3008 mayalso comprise grapples 3014, 3016, and 3018 configured to engage thesurface of a body lumen and restrain the distal anchor 3000 with respectto the body lumen. In some variations, one or more of grapples 3014,3016, and 3018 may be omitted. In other variations, additional grapplesare added.

FIG. 31 depicts a portion 3100 of a distal anchor comprising innerfoldable member 3102 and proximal-most foldable member 3104. Innerfoldable member 3102 may comprise a geometry similar to any of the innerfoldable members described herein. Proximal-most foldable member 3104may comprise a distal protrusion 3106 and outer region 3108. Distalprotrusion 3106 may comprise a geometry similar to any of theprotrusions described herein. Outer region 3108 may comprise a geometrysimilar to any of the outer regions of the proximal-most foldablemembers described herein. Proximal-most foldable member 3104 alsocomprises a moveable protrusion 3110 on its distal surface, a recess3112 on its proximal surface, and a grapple 3114 on its proximalsurface. Moveable protrusion 3110 and recess 3112 may be aligned tocreate a region of reduced thickness in proximal-most foldable member3104. Recess 3112 and grapple 3114 may be interconnected so that grapple3114 enters and grips the tissue of a body lumen as inner foldablemember 3102 connects with proximal-most foldable member 3004. Morespecifically, as the proximal surface of inner foldable member 3102engages with moveable protrusion 3110, the protrusion is forcedproximally, thereby forcing distal recess 3112 proximally. Distal recess3112 and grapple 3114 may be integrally coupled so that grapple 3114moves proximally and inwardly as distal recess 3112 moves proximally. Inthis way, the proximal motion of inner foldable member 3102 istranslated to a proximal and inward motion of grapple 3114, therebyfacilitating entering and gripping of the tissue.

Protrusion 3110 is depicted as circular, but in some variationsprotrusion 3110 is non-circular. When circular, protrusion 3110 might becharacterized as an arc with a radius that intersects the distal surfaceof an inner region of proximal-most foldable member 3104. In somevariations, the radius of the arc is described as a percentage of thediameter of the proximal-most foldable member and may sometimes be 1%,2%, 3%, 4%, 5%, 10%, 15%, 20%, 25%, 30%, or any percentage range betweenany two of the above percentages. In some variations, the arc does nothave a constant radius. In some variations, protrusion 3110 may be lessresistant to movement than surrounding areas of the proximal-mostfoldable member 3104. In this way, protrusion 3110 may be configured tomove relative to the surrounding area of proximal-most foldable member.In some variations, the reduction in resistance to deformation isfacilitated by a decrease in the thickness of the proximal-most foldablemember 3104 in the area of the protrusion 3110. In other areas, thedensity of the material is reduced in the area of the protrusion 3110.Although FIG. 31 depicts proximal-most foldable member 3104 ascomprising a single protrusion configured to move relative to thesurrounding area, other variations may have any number of suchprotrusions, including 2, 3, 4, 5, 6, 7, 8, 9, and 10 protrusion.Further, FIG. 31 illustrates a protrusion on the distal surface ofproximal-most foldable member 3102, but some variations may include aprotrusion on the proximal surface of inner foldable member 3102 and aflat surface or protrusion on the distal surface of proximal-mostfoldable member 3104.

Grapple 3114 is illustrated as being “fang” shaped, but in otherembodiments grapple 3114 takes an alternative shape, such as a hookshape, that can puncture the surface of a body lumen. Grapple 3114 maycomprise barbs oriented away from the direction of insertion, therebypreventing withdrawal of the fang after insertion. In some variations,the length of grapple 3114 is described as a percentage of the thicknessof proximal-most foldable member 3104 from its distal-most point to itsproximal-most point, and the percentage may sometimes be 5%, 10%, 20%,30%, 40%, 45%, 50%, 60%, 70%, 80%, 90%, or 95%, or any percentage rangebetween any two of the above percentages. In other variations, thethickness of proximal-most foldable member 3104 from its distal-mostpoint to its proximal-most point is described as a percentage of thelength of grapple 3114, and the percentage may sometimes be 5%, 10%,20%, 30%, 40%, 45%, 50%, 60%, 70%, 80%, 90%, or 95%, or any percentagerange between any two of the above percentages.

Although FIG. 31 illustrates protrusion 3110, recess 3112, and grapple3114 positioned near an edge of foldable member 3104, other variationsmay have the grapple positioned at any location on proximal-mostfoldable member 3104. In some variations, the position of the protrusion3110, recess 3112, and grapple 3114 is characterized as a percentage ofthe radius of the proximal-most member and may sometimes be 5%, 10%,20%, 30%, 40%, 45%, 50%, 60%, 70%, 80%, 90%, or 95%, or any percentagerange between any two of the above percentages. Further, althoughportion 3100 is described with an inner foldable member, a distal-mostfoldable member may replace inner foldable member 3102 without deviatingfrom the scope of the disclosure.

FIG. 32 illustrates a delivery device 3200 configured to transport oneor more foldable members through a fistula tract and into a body lumen.Delivery device 3200 may be configured to reduce the cross-sectionalprofile of the foldable members so that the foldable members can beinserted into elongate tubular member 3202 that has an internal diameterless than the diameter of the foldable members. Delivery device 3200 mayalso include a profile reduction member 3204 for reducing thecross-sectional profile of the foldable members to a width no more thanthe diameter of the elongate tubular member 3202. Once the foldablemembers are fully inserted into the elongate tubular member 3202, thetubular member may be passed through a fistula tract until the elongatetubular member is aligned with, or distal to, the distal opening of thefistula tract. The foldable members may then be pushed through thedistal end of elongate tubular member 3202 or elongate tubular member3202 may be withdrawn to deploy the foldable members in a body lumen.

The interior diameter of the elongate tubular member 3204 may becharacterized as a percentage of the diameter of a proximal-mostfoldable member and may sometimes be 1%, 2%, 3%, 4%, 5%, 10%, 15%, 20%,25%, or any percentage range between any two of the above percentages.In some variations, profile reduction member 3204 is integrallyconnected to elongate tubular member 3202 and in other variations it isconfigured to removably couple to the tubular member. In somevariations, the size and shape of a profile reduction section may beconfigured for a specific foldable member. For example, a distal-mostfoldable member may require a different profile reduction section than alarger proximal-most foldable member.

FIG. 32 depicts a conical profile reduction member 3204. In somevariations, the foldable member may be pushed through the conicalprofile reduction member by a rod. The rod may engage with the foldablemember in the large dimension or the smaller dimension. For example, arod may be used to push a foldable member on its proximal surface sothat the distal surface is forced into the conical section. As thefoldable member is forced further down the conical member and tubularmember, the foldable member may assume a pleated configuration.Additional foldable members may then be inserted into the elongatetubular member.

In some variations, the profile member 3204 includes inner grooves orridges to guide the foldable members into the delivery tube and controlthe folding. The grooves or ridges may be configured to interact withsurface features on the foldable members, such as the surface featuresdescribed above that are configured for relatively restraining twoadjacent foldable members.

FIGS. 33A and 33B depict a side view and perspective view, respectively,of a rod 3300 configured to grasp a foldable member and insert thefoldable member into a delivery device. Rod 3300 may generally comprisea handle 3302, a transition section 3304, and a distal head 3306. Distalhead 3306 may comprise two elongate parallel slits 3310 configured toreceive a foldable member. Each slit may have a distal opening 3308 anda curved proximal end 3312. The rod 3300 may be configured to reduce theprofile of the foldable member by rotating the handle 3302 as the head3306 pushes the foldable member into a profile reduction member. FIG.33B illustrates the head with a hollow central tube. The hollow centraltube may allow for additional folding in the central region of thefoldable member. In some variations, the diameter of the central tube3314 is characterized as a percentage of the diameter 3316 of distalhead 3306 and may sometimes be 5%, 10%, 20%, 30%, 40%, 45%, 50%, 60%,70%, 80%, 90%, or 95%, or any percentage range between any two of theabove percentages. Curved proximal end 3312 may be configured to cradlea perimeter portion of a foldable member. In some variations, thelengths of the elongate slits are characterized as percentages of thelength of the head 3306 and sometimes may be 5%, 10%, 20%, 30%, 40%,45%, 50%, 60%, 70%, 80%, 90%, or 95%, or any percentage range betweenany two of the above percentages.

FIGS. 34A and 34B illustrate top views of a foldable member 3404 before3400 and after 3410 it is folded for insertion. FIG. 34A illustrates thefoldable member 3404 when it is inserted into the slots in the head 3402of an insertion rod. FIG. 34B illustrates the foldable member 3404 afterit has been pushed in a profile reduction member of a delivery device(not shown). The foldable member 3404 in the after configuration 3400generally take a reverse “S” shape. In other variations, the foldablemember takes a different shape, such as a spiral or a wave, for example.

FIGS. 35A and 35B illustrate a proximal perspective view and a distalperspective view, respectively, of push device 3500. Push device 3500may be configured to force one or more foldable members through adelivery tube. Push device 3500 may comprise a suture channel 3508configured to permit a suture connected to a foldable member to be runaxially to the push device while the foldable member is being inserted.Push device 3500 may comprise a handle 3502 and a distal head 3504. Thediameter of distal head 3504 may be larger than the diameter of thehandle 3502 to allow the suture to lie alongside the delivery tube. Thediameter of the head 3504 may approximate the inside diameter of adesired delivery tube. FIG. 35B illustrates a distal perspective view ofpush device 3500, depicting a planar distal surface for pushing thefoldable member through the delivery tube.

FIGS. 36A and 36B illustrate a side view and a distal perspective view,respectively, of push device 3600. Push device 3600 comprises a handle3602 and a head 3604, similar to push device 3500. Push device 3600 mayalso comprise a suture channel 3606 configured to permit a sutureconnected to a foldable member to run axially to the push device duringdelivery. Suture channel 3506 may be oriented at an angle to the mainaxis of push device 3600, wherein the angle may be 0°, 10°, 20°, 30°,40°, 50°, 60°, 70°, 80°, and 90°. Suture channel 3606 may also comprisea suture engagement structure 3610. The angle of suture channel 3606 andthe suture engagement structure 3610 may allow push device to engage andlock the suture within the head 3604 as the push device moves throughthe delivery tube. Engagement and locking of the suture may be achievedby twisting the push device 3600.

Fistula tracts may be nonlinear or curvilinear and may contain cavitiesof varying sizes at different intervals within the tract. Fistulas mayalso comprise multiple interconnected or branching passages. A fistulatreatment device disclosed herein may employ advantageous design,configuration techniques and attributes to accommodate such constraintsand may be used, for example, in the treatment of anorectal fistulas.Some embodiments of fistula treatment devices may comprise irrigationand/or brushing devices which may be used, for example, to clean afistula tract prior to, during, and/or after a procedure, and/or whichmay be used to clean a fistula tract prior to insertion of one or moreimplantable devices or other members (e.g., collagen plugs) therein.

Referring to FIG. 37A, a fistula irrigation device (as shown, a fistulairrigation catheter 3710) comprises a proximal end 3712 and a distal end3714. The fistula irrigation catheter further comprises a tubular member3716 including a wall portion 3718 having a plurality of apertures 3720therethrough. The tubular member has a proximal end 3713 and a distalend 3715. In some embodiments, the length of the tubular member (betweenthe proximal end 3713 and the distal end 3715) may be in the range ofabout 20 centimeters to about 200 centimeters, such as about 40centimeters to about 120 centimeters, about 40 centimeters to about 100centimeters, or about 60 centimeters to about 90 centimeters.

The apertures 3720 may be used to irrigate a fistula tract—in otherwords, one or more irrigation fluids may flow through, or be sprayed orotherwise dispersed via, the apertures 3720. In some embodiments, thedistalmost aperture 20′ may be located at least about 2 centimeters(e.g., at least about 3 centimeters, at least about 4 centimeters, atleast about 5 centimeters, at least about 10 centimeters, at least about20 centimeters, at least about 30 centimeters, at least about 40centimeters, at least about 50 centimeters, at least about 100centimeters) from the distal end 3714 of the fistula irrigation catheter3710. In other words, a fistula irrigation catheter may includeapertures that are offset from the distal end of the catheter. This maybe advantageous because it may, for example, provide for irrigation of agreater region of a fistula tract (e.g., both proximal and distalirrigation) than an irrigation catheter that only has an irrigationaperture at its distal end.

FIG. 37B provides a cross-sectional view of an aperture 3720 in a regionof the wall portion 3718. As shown there, the aperture 3720 has an axis3722 therethrough that defines an angle 3723 relative to the exteriorsurface 3719 of the wall portion 3718. In FIG. 37B, the angle 3723 isshown as orthogonal (i.e., 90°)—however, in other embodiments, such anaperture angle may not be orthogonal. For example, the angle 3723between an axis 3722 of an aperture 3720 and the exterior surface 3719may be at least about 45° (e.g., at least about 60°, at least about 75°,at least about 90°, or from about 45° to about 180°, such as about 75°)relative to the distal end 14 of the catheter 3710, and/or may be atmost about 180° (e.g., at most about 135°, at most about 120°, at mostabout 105°, or from about 45° to about 180°, such as about 75° to about135°, or about 105°) relative to the proximal end 3712 of the catheter3710.

While the apertures 3720 are depicted as generally oval or elliptical inshape, apertures in a fistula irrigation catheter may have any suitableshape, and may all be of the same shape or may have different shapesfrom each other. In some embodiments, an aperture may be circular,triangular, or square. Other appropriate shapes may also be used.Moreover, the apertures may all have the same size or may have differentsizes (e.g., to provide differing amounts of irrigation to differentregions of a fistula tract).

In some embodiments, apertures may be radially positioned around afistula irrigation device. For example, FIG. 37C shows a fistulairrigation catheter 3740 having a proximal end 3742 and a distal end3744, and comprising a tubular member 3746 having a wall portion 3748having a plurality of radially disposed apertures 3750 therethrough,including distalmost apertures 3750′. As shown there, the apertures arearranged in two radial configurations. However, other embodiments offistula irrigation catheters may have different arrangements and numbersof apertures. As an example, FIG. 37D shows a fistula irrigationcatheter 3760 having a proximal end 3762 and a distal end 3764, andincluding a tubular member 3766 having a wall portion 3768. The tubularmember 3766 has a plurality of apertures 3770 therethrough, includingdistalmost apertures 3770′. Of course, other configurations arepossible, and any suitable number, size, shape and arrangement ofapertures may be used in a fistula irrigation device.

In certain embodiments, apertures may be radially positioned around anirrigation catheter, and may be the distal termination points ofradially oriented tubular members or lumens within the irrigationcatheter. In some embodiments, a fistula irrigation device may compriseone or more infusion lumens that terminate at the location of one ormore apertures in the device, such that the lumens do not extend anyfurther distally, thereby avoiding creating “dead space” within thedevice. In certain embodiments, a fistula irrigation device may includeone or more infusion lumens that extend distally beyond one or moreapertures in the device; however, in some such embodiments, the infusionlumens may be plugged or otherwise filled distally of the apertures. Insuch cases, a guidewire lumen may be maintained open.

The tubular member 3716 of the fistula irrigation catheter 3710 may berelatively flexible in some embodiments and in certain embodiments, mayinclude one or more relatively rigid regions. This may, for example,allow the tubular member 3716 to conform well to a tissue tract duringuse.

In certain embodiments, a fistula irrigation catheter may also havefistula brushing or debriding capabilities. As an example, FIG. 38Adepicts a fistula irrigation and brushing catheter 3800. The catheter3800 includes features similar to those described above with respect tothe fistula irrigation catheter 3710, such as irrigation apertures 3802.However, the catheter 3800 also includes a brushing member 204 havingbristles 3806. When the catheter 3800 is used to irrigate a fistulatract, it may also be used to brush or debride the fistula tract,thereby further cleaning the tract. In some cases, the bristles 3806 maybe formed of one or more polymers. Other appropriate materials may alsobe used. In certain embodiments, a sheath or other protective member(not shown) may be removably positioned over a brushing member to, forexample, temporarily prevent the brushing member from brushing tissue(e.g., non-target tissue).

Of course, brushing members having different configurations may be used.For example, FIG. 38B shows a portion of a fistula brushing catheter3820 having bristles 3822 arranged similar to the bristles of atoothbrush, and FIG. 38C shows a portion of a fistula brushing catheter3830 having bristles 3832 arranged in a spiral pattern. Additionally,FIG. 38D shows a fistula brushing catheter 3840 having two sets ofradially disposed bristles 3842. Of course, these are only exemplaryembodiments, and other bristle arrangements may be used in fistulabrushing devices. Moreover, some embodiments of fistula brushing devicesmay include bristles in different regions from those depicted herein.

It should be understood that while combination fistula irrigation andbrushing or debriding devices have been described, in some cases afistula treatment device may be configured to brush or debride a fistulatract without also irrigating the tract. Additionally, in someembodiments a fistula brushing device may not be in the form of acatheter. As an example, FIG. 39 shows a fistula brushing device 3900comprising a proximal handle portion 3902, a shaft 3904 extending fromthe handle portion 3902, and a brushing member 3906 comprising bristles3908, where the brushing member 3906 is located in a distal portion 3910of the shaft 3904. Of course, while not shown here, certain embodimentsof fistula brushing devices may include multiple brushing members, ormay include one or more brushing members that are not located in adistal portion of the device or a component thereof. As shown, thefistula brushing device 3900 also comprises an elongated member 3912,such as a suture or a string which may be used, for example, to helproute the device 3900 into a fistula tract. For example, the elongatedmember 3912 may be attached to a guidewire that has been routed into afistula tract, and the guidewire may be pulled upon to advance thefistula brushing device 3900 into the fistula tract. In someembodiments, however, a fistula treatment device may not include such anelongated member, or alternatively may include multiple such elongatedmembers.

Any appropriate methods may be used to deliver or deploy the fistulatreatment devices described herein. For example, FIGS. 40A-40C depict anembodiment of a method of delivering the fistula irrigation catheter3710 of FIG. 37a into an anorectal fistula tract 4000. First, FIG. 40Ashows the fistula tract 4000, by the anus 4002 and the dentate line4004. In FIG. 40B, a guidewire 4006 has been passed through the fistulatract 4000. Next, and referring to FIG. 40C, the fistula irrigationcatheter 3710 has been delivered into the fistula tract 4000, over theguidewire 4006. The guidewire 4006 may be maintained within the catheter3710 in the fistula tract 4000, or may be removed at this point.

Once the tubular member 3716 with the apertures 3720 is located withinthe fistula tract, the fistula irrigation catheter 3710 may be graspedat both its proximal and distal ends 3712 and 3714, and moved back andforth within the tract 4000 (e.g., as illustrated by arrow 4008), toeffectively “floss” the tract 4000 and thereby irrigate differentregions of the tract 4000. This may, for example, provide for goodcleaning and minimal contamination of the fistula tract 4000 (e.g., byproviding for both proximal and distal irrigation of the fistula tract).Moreover, and as discussed above, the apertures 3720 may be oriented tospray irrigation fluid (e.g., saline) in a non-orthogonal direction—forexample, some of the apertures 3720 may be forward-angled and some ofthe apertures 3720 may be backward-angled, so that bidirectionalirrigation may be provided. Additionally, it should be noted that, whilenot shown here, fistula brushing members or devices may also be movedback and forth within a fistula tract in the manner described above.

To perform the procedures described above, a kit may be provided thatcontains, for example, one or more fistula irrigation devices, one ormore fistula brushing devices, and/or one or more combination fistulairrigation and brushing devices. The kit may also contain one or moreother items, including but not limited to a guidewire (e.g., a 0.038″guidewire), a peel-away sheath (e.g., a 7F, 8F, 9F, 10F, or 12F sheath),one or more syringes (e.g., 0.5 cc, 1 cc, 5 cc, and/or 10 cc syringes),saline or biocompatible fluid, contrast media, a scalpel, one or morefree needles, and non-resorbable sutures (e.g. 3-0 or 4-0 nylon suture).A fistula tract dilator may also be provided in the kit. The contents ofa kit may be provided in sterile packages. Instructions may be providedon or with the kit, or alternatively via the Internet or anotherindirect method, and may provide direction on how to employ the kit(e.g., outlining a deployment method such as one of those describedherein). While preferred embodiments of the present invention have beenshown and described herein, it will be obvious to those skilled in theart that those examples are brought by way of example only. Numerouschanges, variations, and substitutions will now occur to those skilledin the art without departing from the invention. It should be understoodthat various alternatives to the embodiments of the invention describedherein may be employed in practicing the invention. It is intended thatthe following claims define the scope of the invention and that themethods and structures within the scope of these claims will be coveredthereby.

What is claimed is:
 1. A distal anchor for an implantable fistulatreatment device, the distal anchor comprising: a suture; and adistal-most foldable member comprising a suture attachment structure;and a proximal-most foldable member configured to slide along the sutureand couple to a surface of a body lumen at a distal opening of a fistulato occlude the fistula at the distal opening, wherein a diameter of theproximal-most foldable member is larger than a diameter of thedistal-most foldable member, wherein at least one of the foldablemembers comprises a protrusion on a first surface, and wherein at leastanother of the foldable members comprises a recess on a second surfacethat opposes the first surface, wherein the protrusion and the recesscomprise complementary coupling members, such that the recess isconfigured to receive the protrusion to restrain relative movement ofthe foldable members.
 2. The distal anchor of claim 1, furthercomprising at least one additional foldable member positioned betweenthe distal-most foldable member and the proximal-most foldable member.3. The distal anchor of claim 2, wherein the at least one additionalfoldable member comprises at least one protrusion and at least onerecess.
 4. The distal anchor of claim 1, wherein the proximal-mostfoldable member comprises a generally circular perimeter.
 5. The distalanchor of claim 4, wherein the proximal-most foldable member comprises agenerally concave shape.
 6. The distal anchor of claim 5, wherein thedistal-most foldable member comprises a generally concave shape, andwherein a radius of curvature of the distal-most foldable member issmaller than a radius of curvature of the proximal-most member.
 7. Thedistal anchor of claim 1, wherein the protrusion on the at least onefoldable member comprises at least one tooth.
 8. The distal anchor ofclaim 1, further comprising an additional coupling member disposedbetween the foldable members, wherein the additional coupling membercomprises a curing agent.
 9. The distal anchor of claim 8, wherein theadditional coupling member further comprises a capsule enclosing thecuring agent.
 10. The distal anchor of claim 9, wherein the capsule isconfigured to rupture upon contact with another foldable member.
 11. Thedistal anchor of claim 1, wherein the coupling members are configured toproduce attracting electromagnetic forces.
 12. The distal anchor ofclaim 1, wherein the proximal-most foldable member is more flexible thanthe distal-most foldable member.
 13. The distal anchor of claim 12,wherein a density of the proximal-most foldable member is less than adensity of the distal-most foldable member.
 14. The distal anchor ofclaim 1, wherein a proximal surface of the proximal-most foldable membercomprises a grapple configured to attach the proximal-most foldablemember to a surface of the body lumen.
 15. The distal anchor of claim14, wherein a distal surface of the proximal-most foldable membercomprises a grapple activation structure configured to activate thegrapple upon contact with the proximal surface of another foldablemember.
 16. The distal anchor of claim 15, wherein the grappleactivation structure comprises a protrusion.
 17. The distal anchor ofclaim 1, wherein the protrusion comprises at least two protrusions, andwherein the recess comprises at least two recesses.
 18. The distalanchor of claim 1, wherein the distal-most foldable member ispre-attached to the suture at the suture attachment mechanism.
 19. Thedistal anchor of claim 18, wherein the proximal-most foldable member isnot pre-attached to the suture.